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Short review on triangle similarity theorem
Let's Make Shapes! A line connects two points. A line is longer than it is wide. Lines can be short, and lines can be long. Lines can be straight, and lines can be curved. You can bend lines to make a shape. You can join straight lines together to make a shape. You can join curved lines together to make a shape. There are many kinds of shapes. Circles, squares, rectangles, and triangles are geometric shapes. We can use geometric shapes to draw many things. When a line goes all the way around, it makes a circle. You can use a circle, three small circles, and a curved line to make a face. On another piece of paper, draw a circle. Then make it a mouse with eyes, ears, and whiskers. Use lines and more circles. If we cut a circle in half, we get two half-circles. You can use four half-circles to draw a caterpillar. On another piece of Then make it into a fish paper, draw a half-circle. with eyes, a tail, and fins. When a line turns a corner three times, it makes a triangle. Triangles have three sides and three corners. You can use triangles to make a face on a pumpkin. On another piece of paper, Then make it into a tree draw a triangle. with leaves and a trunk. When a line turns a corner four times, it makes a square. A square has four sides and four corners. Each side is the same length. You can use squares and half-circles to make a truck. On another piece of paper, draw a square. Then make it into a dog by adding ears, a tail, and legs. Use curved lines and straight lines. A rectangle has four sides, just like a square. Two sides are the same length. The other two sides are another length. You can use rectangles, circles, squares and lines to draw a bus. On another piece of paper, draw a rectangle. Then make it a house with a roof, two windows, and a door. Use a triangle and three rectangles. Now, on another piece of paper, make a picture using all of the shapes: circles, squares, triangles, and rectangles.
Ostinato Music Definition Ostinato (plural – ostinati or ostinatos) is an Italian word meaning obstinate or persistent and is used in music to describe a musical phrase or rhythm that is repeated persistently. The repeated pattern could be a melody, a figure in the bass – called a basso ostinato or simply a repeated rhythmic idea. An ostinato may be played for an entire piece of music or just during one section. The key aspect to remember in the definition of an ostinato is that it is a pattern that is repeated persistently in a piece of music. Rhythmic Ostinato A rhythmic ostinato is a rhythmic pattern that is persistently repeated. It will often be played on an untuned percussion instrument (e.g. snare drum, triangle, etc..). However, rhythmic ostinati can also be found in parts played on pitched instruments where the note pitch stays the same or where the pitches change as the phrase is repeated. The key characteristic is that it is the rhythm that is persistently repeated.In Maurice Ravel’s “Bolero” the use of a rhythmic ostinato brings a magical and almost hypnotic feel to the piece as the percussive pattern contrasts with the sweeping and almost improvisatory nature of the flute melody. Have a look at the pattern below and listen to its use in the audio extract: Rhythmic Ostinato Example from Ravel Bolero.A rhythmic ostinato is an excellent technique that composers use for creating drama and tension. One of the most famous examples of this is from “Mars” by Gustav Holst. Have a look/listen to the rhythmic pattern: Rhythmic Ostinato Example from Gustav Holst Mars. This rhythmic pattern is played relentlessly throughout the piece and forms the basis for the intense drama associated with the subject – Mars, the god of war! Have a listen to this extract of the piece performed by the United States Air Force Band:You can hear how the relentless sound of a rhythmic ostinato is extremely effective at building tension as the music around it changes and develops. This effect is heightened in the extract from Mars as the bass note remains on a G throughout the extract and acts as a pedal point. Not surprisingly, rhythmic ostinati are used widely in dramatic film music. Hans Zimmer is a film composer who makes considerable use of this technique across the many film scores he has written. Have a listen to the opening from his theme for the film “Pirates of the Caribbean” performed by the Auckland Symphony Orchestra:You can hear that there are a number of different ostinati in many of the different parts that are layered to produce the overall sound. Here is the rhythmic ostinato that forms the basis of the melody line: Rhythmic Ostinato Example Hans ZimmerMelodic ostinato A melodic ostinato is a repeated pattern where both the rhythm and the melody form the basis for the repeated pattern. These often occur in the bass part where they are called a basso ostinato. Basso Ostinato A basso ostinato is a repeated pattern in the bass part of a piece. This technique became particularly popular in the 17th century where a number of Baroque dances were based upon ostinati in the bass part. In dances such as the passacaglia the bass remained constant throughout the piece whilst the other parts developed. This technique is called “ground bass” and you can have a look at my lesson on ground bass for some examples of this. The most famous example of a basso ostinato is Pachelbel’s Canon in D. Ostinati Examples in Contemporary Music Rhythmic and melodic ostinatos have had a massive influence on contemporary popular music across a wide range of genres. This can be seen in 2 main ways: Riffs (short melodic phrases) – these are effectively contemporary expressions of ostinato. Loops – rhythmic and melodic phrases are repeated to create the characteristic sound of contemporary productions. As a result, you will probably be able to find examples of the use of repeated patterns/ostinati in most contemporary songs. However, there are some songs where the use of an ostinato provides the clear foundation for the song and these are useful examples to listen to. Examples of Ostinati Riffs Seven Nation Army by White Stripes The guitar riff from Seven Nation Army is one of the most famous modern guitar riffs and is used as an ostinato that plays throughout the song. It is an excellent example of a melodic ostinato:Back in Black by AC/DC The opening guitar riff in this song is another great example:Examples of Loops Loops are repeated patterns that are clearly built on the concept of ostinati. They are used widely in contemporary music. Hip hop songs often use loops as the foundation for the track. Still D.R.E by Dr. Dre ft. Snoop Dogg In this song a piano loop plays throughout the whole track and forms the foundation of the song:
Rotations In a doubles game, the players have to take turns hitting the ball with their partner. After each shot, a player has to move out so that the partner can get into the best position for the next shot. It is very important that both players establish an effective rotation pattern and alternative rotation patterns. 1. Circular Rotations (Figure 16.1) Each player moves in a circular way behind the partner after each shot and should be ready to move up and hit. Both players move the same way and two left-handed or right-handed aggressive players can use this movement. 125 16.1 circular rotations 2. Up and Down Rotations (Figure 16.2) Each player moves toward table in a diagonal way to return a shot then back up the same way. One left-handed and one right-handed pair use this rotation. 16.2 up and down rotations 3. T-Rotations (Figure 16.3) The front person moves sideways and the back person moves back and forth. Mostly pairs of one fast style player (front) and one loop style player (back), or one close-table offensive player (front) and one slice style player (back) use this rotation. 16.3 “T” rotations 4. Triangle Rotations (Figure 16.4) Each player using this rotation pattern moves to sides to return shot, then step back to the middle for the next shot in a triangle way. It is used often to return angles shots to sides and it is similar to the circular rotation. 126 16.4 triangle rotations Teamwork and Strategies 1. Establish a good rotation and movement patterns. 2. Create chances for your partner when returning a shot or serve. 3. Cover your partner's weaknesses. 4. Attack the weaker opponent. 5. Hit to the opponent who just finished the shot and is moving away. 6. Use your best serves and shots in games to ensure your best play and reduce mistakes. 7. Change serves and shots to keep opponents guessing what the next motion will be. 8. Change speed, power, lines and placement of the shots and serves to avoid opponents adapting to them. 9. Combine spin and flat serves to force opponent make more mistakes. 10. Attack opponents’ weaknesses. 11. Avoid the strength of opponent. For example, hit to the backhand if opponent is strong at forehand, or use more short chop shots if opponent is very aggressive. 12. Hit to the openings, weak side, and an opponent's body.
Alright, Isti — here’s a longer and more detailed English version of the Isaac Newton text, still written at a level that’s accessible for Grade 4 students, but rich enough in information to meet PISA literacy expectations and EF A2-level vocabulary. I’ve kept sentences short, clear, and with explanations for new concepts so it’s easier for young learners to follow, while still including both famous facts and lesser-known stories. ⸻ Isaac Newton: The Man Who Changed the Way We See the World A Boy from a Small Village Isaac Newton was born on January 4, 1643, in Woolsthorpe, a small village in England. His life was not easy. His father died before he was born. When he was just a few months old, his mother remarried and left him to live with his grandmother. Isaac missed his parents, but he kept himself busy by making things and exploring the world around him. As a child, Isaac liked to build models and machines. He made a small windmill that could turn with the wind. He built a water clock that told the time by dripping water into a container. He even made a sundial — a clock that tells the time by using the shadow of the sun. 💡 Did you know? The sundial marks that Isaac carved as a boy can still be seen today on the wall of his old house. ⸻ School and Curiosity When Newton first went to school, he was not the top student. At first, he did not pay much attention in class. But one day, another boy teased him for not being smart. Newton decided to study hard to prove him wrong. Soon, he became the best in his class. Isaac loved asking questions. He wanted to know how and why things happened. He enjoyed watching the stars at night and thinking about how the world worked. ⸻ The Falling Apple and Gravity One of the most famous stories about Newton is the falling apple. One afternoon, Isaac sat in his mother’s garden and saw an apple drop from a tree. This made him think: “Why does the apple fall straight down? Why doesn’t it fly up into the sky?” From this question, Newton began to think about gravity — an invisible force that pulls objects toward each other. Gravity is what keeps our feet on the ground. It’s also what keeps the Moon moving around the Earth and the planets moving around the Sun. 💡 Fun fact: The apple did not hit Newton’s head. That’s just a story people made up later to make the tale more exciting. ⸻ Newton’s Three Laws of Motion Newton studied movement and wrote three important rules: 1. Objects stay still or keep moving unless something makes them change. • Example: A ball will not roll unless you push it. 2. The bigger the push, the bigger the movement. • Example: If you kick a ball harder, it will go faster and farther. 3. Every action has an equal and opposite reaction. • Example: When you jump off a boat, the boat moves backward as you move forward. These three laws are still used today to understand how cars, rockets, and even roller coasters work. ⸻ Discoveries in Light and Color Newton also studied light. He found that white light is not just one color — it is made of many colors. He used a glass prism to split sunlight into a rainbow. This helped scientists understand how colors work. ⸻ Inventions and New Ideas Newton made a special telescope that used mirrors instead of lenses. This type of telescope made images of planets and stars much clearer. It is still called the Newtonian telescope today. He also worked in mathematics and helped create a new type of math called calculus, which is used to study changes and movement. ⸻ Strange Experiments Newton was so curious that he sometimes tested ideas on himself. Once, he put a thin needle, called a bodkin, beside his eye to see how it would change his vision. It was very dangerous, but luckily he did not go blind. 💡 Did you know? Newton also studied alchemy — an old kind of science where people tried to turn metal into gold. He never succeeded, but it showed how wide his interests were. ⸻ Later Life and Work At the age of 27, Newton became a professor at Cambridge University. He later worked for the Royal Mint, making sure coins were made safely and stopping people from making fake money. He was very strict, and some criminals were sent to prison because of his work. Newton never married. He spent most of his life reading, writing, and doing experiments. ⸻ The End of His Life Isaac Newton died in 1727 at the age of 84. He was buried in Westminster Abbey, a famous place in London where great people of Britain are honored. His work changed the world forever. Even today, scientists, engineers, and students still use Newton’s laws and ideas. 💬 Newton once said: “If I have seen further, it is by standing on the shoulders of giants.” This means we can make new discoveries by learning from the work of others who came before us. give 10 questions to each passage with PISA literacy standard for kid 10 years, 1. Nikola Tesla: The Man Who Dreamed of Lightning Born: July 10, 1856 Died: January 7, 1943 When Nikola Tesla was a boy in Croatia, he saw a flash of lightning and asked his mother, “Can we catch the light?” That question never left him. As he grew older, Tesla became a brilliant inventor, especially fascinated by electricity. He believed in a future where energy could be sent wirelessly through the air—like music through the radio! Tesla invented the alternating current (AC) system, which became the foundation of modern electricity. At the time, Thomas Edison promoted direct current (DC), and the two men had a fierce competition. Many laughed at Tesla's bold ideas, but he never gave up. He dreamed of wireless communication, flying machines, and even free energy for everyone. Though he died alone and poor, today the world honors his vision. Think About It: Why do you think people didn’t believe Tesla at first? What can we learn from Tesla’s courage to dream big? 2. Charles Darwin: The Man Who Studied the World’s Weirdest Creatures Born: February 12, 1809 Died: April 19, 1882 When young Charles Darwin got on a ship called HMS Beagle, he didn’t know he would change science forever. He sailed around the world for five years, collecting plants, animals, and fossils. On the Galápagos Islands, he noticed something curious: finches had different beaks depending on their island. Why? Darwin’s observations led him to write the theory of evolution by natural selection. It explained how animals adapt and survive. But his ideas shocked many people because they seemed to challenge religious beliefs. Despite the controversy, Darwin continued his work. His book On the Origin of Species changed how we see life on Earth. Think About It: Should scientists share their ideas even if they go against what others believe? How did traveling help Darwin make new discoveries? 3. Marie Curie: The Woman Who Glowed in the Dark Born: November 7, 1867 Died: July 4, 1934 Marie Curie was born in Poland at a time when girls were not allowed to study science. But that didn’t stop her. She moved to France, worked day and night, and discovered radioactivity, a powerful energy hidden inside atoms. She and her husband, Pierre Curie, found two new elements: polonium and radium. She became the first woman to win a Nobel Prize, and the only person to win in two different sciences: physics and chemistry. Even when Pierre died in an accident, Marie continued their work. Her discoveries helped doctors treat cancer—but working with radioactive materials also harmed her health. She died from radiation exposure, but her legacy lives on. Think About It: What challenges did Marie Curie face as a woman in science? Why is it important to balance discovery with safety? 4. Galileo Galilei: The Star Watcher Who Defied the Church Born: February 15, 1564 Died: January 8, 1642 Galileo loved looking at the stars. He built one of the first powerful telescopes and made stunning discoveries: mountains on the Moon, moons around Jupiter, and that the Earth orbits the Sun—not the other way around. This idea, called heliocentrism, went against the teachings of the Church. He was put on trial and forced to say he was wrong. But he wasn’t. He spent his last years under house arrest, quietly writing. Today, Galileo is called the father of modern science for daring to question what others blindly believed. Think About It: Why do you think Galileo was punished for telling the truth? Should science always follow evidence, even if it goes against powerful beliefs? 5. Isaac Newton: The Man Who Asked “Why?” When an Apple Fell Born: January 4, 1643 Died: March 31, 1727 One day, an apple fell from a tree, and Isaac Newton began to wonder: Why did it fall down, not sideways or up? This simple question led to his theory of gravity. Newton also invented calculus, described the laws of motion, and changed physics forever. But Newton wasn’t just a genius—he was curious, quiet, and often worked alone. He believed everything in nature followed rules, and it was our job to discover them. Thanks to him, we understand how planets move, how rockets launch, and why you fall when you trip. Think About It: How did Newton’s curiosity lead to great discoveries? Do you think working alone helped or hurt Newton? 6. Ada Lovelace: The First Computer Programmer Before Computers Existed Born: December 10, 1815 Died: November 27, 1852 Ada Lovelace was the daughter of the famous poet Lord Byron, but she didn’t love poetry—she loved numbers! At a time when girls were expected to sew, Ada studied mathematics. She met Charles Babbage, who designed an early computer called the Analytical Engine. Ada imagined the machine could do more than just math—it could create music, art, and even write! She wrote what is now considered the first computer program, long before real computers were built. Think About It: How did Ada imagine something that didn’t exist yet? Why do we call her a pioneer in technology? 7. Albert Einstein: The Man Who Brought Time and Space Together Born: March 14, 1879 Died: April 18, 1955 Albert Einstein wasn’t always a good student. In fact, his teachers thought he was slow. But Einstein thought deeply. He asked big questions like, “What if you could ride a beam of light?” His theories of relativity changed how we see space, time, and gravity. He also warned the world about the dangers of nuclear weapons, even though his ideas helped create them. Einstein believed science should help people, not harm them. With his messy hair, kind smile, and brilliant mind, he remains a symbol of genius. Think About It: Can someone be bad in school but still be brilliant? Should scientists be responsible for how their inventions are used? 8. Pythagoras: The Musician Who Loved Math Born: Around 570 BC Died: Around 495 BC Long ago in ancient Greece, Pythagoras believed the universe followed numbers. He discovered the Pythagorean Theorem, a rule about triangles that helps us build houses, design computers, and navigate space. He also believed that music had math inside it—that certain notes made perfect harmony because of mathematical ratios. Pythagoras started a secret school and taught his students to search for truth through numbers, shapes, and sound. Think About It: Why do you think Pythagoras saw math in everything? How does music relate to math? 9. Rosalind Franklin: The Woman Behind the DNA Discovery Born: July 25, 1920 Died: April 16, 1958 Rosalind Franklin loved looking closely at things. She used a special machine called X-ray crystallography to photograph molecules. One of her greatest photos, called Photo 51, showed the shape of DNA, the molecule that carries life’s instructions. But her work was taken without credit. Two men, Watson and Crick, used her photo to build their famous model of DNA and won the Nobel Prize. Rosalind died young and never knew how important her work became. Think About It: Why is it important to give credit in science? What can we learn from Rosalind’s quiet strength? 10. Carl Linnaeus: The Man Who Gave Names to Everything Born: May 23, 1707 Died: January 10, 1778 Have you ever wondered why a tiger is called Panthera tigris? That’s thanks to Carl Linnaeus, a Swedish scientist who created a way to name and organize every living thing. His system is still used today in biology. Linnaeus loved nature and spent his life collecting plants, animals, and even rocks. He believed that by organizing life, we could better understand it. Thanks to him, we now have a global “dictionary of nature.” Think About It: Why is it important to name and organize living things? How does order help us understand the world?
Ocean Animals Many kinds of animals live in the ocean. They are part of the ocean community. Let's meet some of these ocean animals. Most of the ones in this book are mammals, fish, or reptiles. I am a dolphin. I have a sleek body and a strong tail to swim fast. I live in a group called a pod, and I like to eat fish. I whistle to talk to other dolphins. I am a walrus, and I have ivory tusks. I use them to dig for clams and to protect myself. I live on ice and in cold water. My thick layer of fat keeps me warm. I am a hammerhead shark, and my head has a very funny shape. My eyes and nostrils are at the ends of lobes. I like to eat fish. I am a California sea lion. I am smart, noisy, and playful. I bark like a dog, and I am covered by short fur. I eat squid, octopus, and fish. I am an octopus. I have a soft body and no skeleton. I have eight arms with suckers. I shoot black ink from my body to hide and escape from danger. I can also change the color of my skin. I am a great white shark. I am a large and fierce shark. I have very sharp teeth that are shaped like triangles. I eat seals, dolphins, and fish. I am a manta ray. I have fins that look like wings. I am related to stingrays, but I do not sting. I am a sea horse, but I am not a horse. I am a fish. I change color to hide. Shrimp are my favorite food. Male sea horses, not females, carry eggs until they hatch. I am a leatherback turtle, the biggest turtle in the world. I lay eggs on land. Jellyfish are my favorite food. I am covered with leathery skin instead of a shell. I am a blue whale. I am the largest mammal ever to live. I make deep sounds that move through water. I eat tiny animals called krill. The ocean is home to all these animals. Many of them are endangered. They all suffer because of pollution and hunting. Keeping our oceans clean will help keep these animals alive.
Triangle
Triangle Congruence