parts of a circle

who actually memorizes this

circle

the set of points equal distance from the given point (the center)

radius

• a segment with an end point at the center

• on the circle

Radii

plural for radius

chord

a segment with endpoints on the circle

diameter

a chord that passes through the center

secant

a line that intersects the circle in two places

tangent

a line that intersects the circle at exactly one place

point of tangency

the point at which the tangent line intersects the circle

central angle

an angle with a vertex at the center and sides that use radii

inscribed angle

• an angle with a vertex on the circle

• two sides that are chords

arc

a portion of the edge of the circle defined by two endpoints

minor arc

• an arc with a measure less than 180°

• two letters to measure it

major arc

• an arc with a measure greater than 180°

• three letters to measure it

semicircle

an arc with the end point on the diameter