the segment with endpoints (x1, y1) and (x2, y2)

(h, k)

r

sqrt[(x₂-x₁)+(y₂-y₁)}

((x₁+x₂/2), (y₁+y₂/2))

(x-h)²+(y-k)²=r²

a line in the plane of the circle that intersects the circle at exactly one point

the point where a circle and tangent line intersect each other

a triangle (or any polygon) that is outside of a circle where each side of the triangle is tangent to the circle

a part of the circle that helps create its perfect circular shape

an arc that is half of the circle

an arc that is smaller than 180 degrees

an arc that is larger than 180 degrees

a segment whose endpoints are on a circle

an angle whose vertex is on the circle and whose sides are chords of the circle

an arc with endpoints on the sides of an inscribed angle

a line that intersects a circle at two points on the circle

the measure of an inscribed angle is half the measure of its intercepted arc

a polygon with four sides

a quadrilateral with 2 sets of parallel sides

a parallelogram with 2 sets of congruent sides

a parallelogram with 4 congruent sides and opposite angles congruent

a parallelogram with 4 congruent sides and 90 degree angles

a quadrilateral with one set of parallel lines