| A | B |
|---|
| circle | the set of all points in a plane that are a given distance from a given point called the center of the circle |
| secant | a line that intersects a circle in two points |
| chord | a segment whose endpoints are on the circle |
| diameter | a chord that contains the center of a circle |
| tangent | a line that intersects a circle at exactly one point |
| arc of a circle | a set of points along a circle defined by a central angle |
| semicircle | an arc whose endpoints lie on a diameter of a circle |
| minor arc | an arc that is part of the circle in the interior of the central angle with measure less than 180° |
| major arc | an arc that is part of the circle in the exterior of the central angle |
| central angle | an angle formed when the two sides of an angle meet at the center of a circle |
| circumference | the distance around a circle |
| inscribed angle | an angle whose vertex is on the circle and whose sides contain chords of the circle |
| concentric circles | circles that lie in the same plane, have the same center, and have radii of different lengths |
