| A | B |
|---|
| chord | For a given circle, a segment with endpoints that are on the circle |
| circumference | The distance around a circle |
| arc | A part of a circle that is defined by two endpoints. |
| tangent | A line in the plane of a circle that intersects the circle in exactly one point. |
| secant | Any line that intersects a circle in exactly two points |
| diameter | In a circle, a chord that passes through the center of the circle. |
| radius | In a circle, any segment with endpoints that are the center of the circle and a point on the circle. |
| circle | The locus of all points in a plane equidistant from a given point called the center of the circle |
| pi | An irrational number represented by the ratio of the circumference of a circle to the diamter of the circle |
| central angle | An angle that intersects a circle in two points and has its vertex at the center of the cirle |
| inscribed | A polygon within a circle where all of the vertices of the polygon lie on the circle |
| circumscribed | A circle around a polygon where the circle contains all the vertices of the polygon |
| point of tangency | For a line that intersects a circle in only one point, the point at which they intersect |
