| A | B |
|---|
| Circle | set of all points in a plane that are equidistant from a given point |
| center | used to name a circle |
| radius | distance from the center to a point on the circle |
| congruent | two circles are this if they have the same radius |
| diameter | the distance across the circle, twice the radius |
| chord | a segment whose endpoints are points on the circle |
| secant | a line that intersects a circle in two points |
| tangent | line in the plane of a circle that intersects the circle in exactly one point |
| tangent circles | coplanar circles that intersect in one point |
| concentric | coplanar circles that have a common center |
| common tangent | a line or segment that is tangent to two coplanar circles |
| interior of a circle | the points that are inside the circle |
| exterior of a circle | the ponts that are outside the circle |
| point of tangency | the point at which a tangent line intersects the circle to which it is tangent |
| central angle | an angle whose vertex is the center of a circle |
| minor arc | arc less than 180 |
| major arc | are more than 180 |
| semicircle | endpoints of the arc are the diameter |
| congruent arcs | arcs in the same or different circles that have smae measure |
| inscribed angle | an angle whose vertex is on a circle and whose sides contain chords of the circle |
| intercepted arc | arc that lies in the interior of an inscribed angle and has endpoints on the angle |
| inscribed | if all of the vertices of a polygon lie on a circle |
| circumscribed | if the polygon is inscribed in the circle then the circle is |
| standard equation of a circle | (x-h) + (y-k) =r |
| locus | set of all points in a plane that satisfy a given condition |
