Geometry 11.3 Vocab

Circle

set of all points equidistant from a given point

Center

the given point of the circle

Diameter

a segment with both end points on the circle that goes thru the center of the circle

Radius

segment with one end point at the center and other end point of the circle

Central Angle

angle whose vertex is the center of the circle

Arc

part of a circle

Minor Arc

less than 180 degrees, name with endpts and symbol (2 letters)

Major Arc

more than 180 degrees, name with endpts. symbol, and any other pt. on the arc (3 letters)

Semicircle

= 180 degrees, name with 2 or 3 letters and symbol

Adjacent Arcs

arcs of the same circle with exactly 1 pt in common

Circumference

distance around the circle

Area

*πr*^2

Concentric

coplanar circles with the same center

Arc Length

“L”, fraction of circumference,

≅ Arcs

arcs that have the same measure and are in the same circle or in ≅ circles

Chord

segment with both endpts on the circle

Sector of circle

fraction of circles area, region bounded by an arc of the circle and 2 radii “piece of pie”