# Circles Ch 10

## 19 terms

### circle

set of all points in a plane equidistant from a given point called the center of the circle

### interior

points inside circle

### exterior

points outside circle

### chord

segment whose endpoints are on the circle

### diameter

chord passing through the center

segment with the center as one endpoint and a point on the circle as the other endpoint

### tangent

line that intersects a circle at one point

### point of tangency

point where a tangent intersects a circle

### secant

line that intersects a circle in two points

### common tangent

line tangent to two circles

### common external tangent

tangent that doesnt intersect the segment by joining the two centers of the circles

### common internal tangent

tangent that does intersect the segment joining the two enters of the circles

### concentric circles

circles with the same center but different radii

### congruent circles

circles with congruent radii or diameter

### arc

measure in degrees between two points on a circle

### central angle

angle whose vertex is the center of the circle

### minor arc

usually denoted with two letters

### major arc

usually denoted with three letters

### semicircle

arc with endpoints that are the endpoints of a diameter