How can we help?

You can also find more resources in our Help Center.

Circle Vocab

the set of all points in a plane that are equidistant from a given point
the distance from the center to a point on the circle
congruent circles
two circles with the same radius
a segment whose endpoints are points on the circle
a line that intersects a circle in two points
a chord that passes through the center of the circle, distance across the circle
a 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 circles
coplanar circles that have a common center
common tangent
a line or segment that is tangent to two coplanar circles
interior of a circle
consists of the points inside the circle
exterior of a circle
consists of the points outside the circle
point of tangency
the point at which a tangent line intersects the circle to which it is tangent
arc addition postulate
says that the measure of an arc formed by two adjacent arcs is the sum of the measures of the two arcs
inscribed angle
an angle whose vertex on a circle and whose sides contain chords of the circle
intercepted arc
the arc that lies in the interior of an inscribed angle and has endpoint on the angle
tangent segment
is tangent to a circle at one of its endpoints
mutually tangent circles
tangent circles