Word | Definition |
center of a circle | see circle |
central angle | an angle whose vertex is the center of the circle |
chord | a segment whose endpoints are on a circle |
circle | the set of all points in a plane that are equidistant from a given point called the center of the circle |
circumscribed circle | the circle that contains the vertices of an inscribed polygon |
congruent arcs | two arcs that have the same measure and are arcs of the same circle or of congruent circles |
congruent circles | two circles that have the same radius |
diameter of a circle | a chord that passes through the center of a circle; the distance across a circle through its center |
external segment | the part of a secant segment that is outside the circle |
inscribed angle | an angle whose vertex is on a circle and whose sides contain chords of the circle |
inscribed circle | a polygon whose vertices all lie on a circle |
intercepted arc | the arc that lies in the interior of an inscribed angle and has endpoints on the angle |
major arc | part of a circle that measures between 180 degrees and 360 degrees |
measure of a major arc | the difference between 360 degrees and the measure of the related minor arc |
measure of a minor arc | the measure of the arc's central angle |
minor arc | part of a circle that measures less than 180 degrees |
radius | a segment whose endpoints are the center of the circle and a point on the circle; the distance from the center of a circle to any point on the circle; plural radii |
secant line | a line that intersects a circle in two points |
secant segment | a segment that contains a chord of a circle and has exactly one endpoint outside the circle |
segments of a chord | when two chords intersect in the interior of a circle, each chord is divided into two segments called segments of the chord |
semicircle | an arc with endpoints that are the endpoints of a diameter of a circle; the measure of a semicircle is 180 degrees |
standard equation of a circle | the standard equation of a circle with center (h, k) and radius r is (x - h) squared + (y - k) squared = r squared |
tangent line | a line in the plane of a circle that intersects the circle in exactly one point, the point of tangency |