arc
a part of a circle that is defined by 2 endpoints
center
point from which all points from the circle are equidistant
central angle
an angle that intersects a circle in 2 points and has its vertex at the center of the circle
chord
for a given circle, a segment with endpoints that are on the circle
circle
the locus of all points in a plane equidistant from a given point called the center of the circle
circumference
the distance around a circle
circumscribed
a circle is circumscribed about a polygon if the circle contains all the vertices of the polygon
diameter
in a circle, a chord that passes through the center of the circle
inscribe
a polygon is inscribed in a circle if each of its vertices lie on the circle
intercepted
an angle intercepts an arc if and only if each of the following conditions are met: 1.) the endpoints of the arc lie on he angle, 2.) all points of the arc except the endpoints are in the interior of the circle, 3.) each side of the angle contains an endpoint of the arc
major arc
an arc with a measure greater than 180
minor arc
an arc with a measure less then 180
pi
an irrational number represented by the ratio of the circumference of a circle to the diameter of the circle
point of tangency
for a line that intersects a circle in only one point, the point at which they intersect
radius
in a circle, any segment with endpoints that are the center of the circle and a point on the circle
secant
any line that intercepts a circle in exactly 2 points
semicircle
an arc that measures 180
tangent
a line in the plane of a circle that intersects the circle in exactly one point. The points of intersection is called the point of tangency