2. An angle formed by 2 radii is called a central angle.
The sum of all central angles with no common interior
points is 360°
The part of the circle the central angle intersects or “cuts”
is called an arc.
A
B
The measure of the arc is equal to the measure of the central angle
3. Types of Arcs
A
B
C
E
D
F
G
H
Minor Arc
Named by endpoints
AB
Major Arc
Named by endpoints
and “go through” point
CDE
Semicircle
Named by endpoints
and “go through” point
FGH
Less than 180°
· · ·
Greater than 180° Equal to 180°
4. A
B
C
D
E F
65°
X
< DXC = < CXB
FIND:
AF =
AB =
< DXC =
DEA =
< EXF =
FDA =
90°
65°
57.5°
180°
25°
270°
5. Favorite Sports
6% 29%
17%
25%
23%
FOOTBALL
BASKETBALL
BASEBALL SOCCER
TRACK
Find the measures of the central angles
360° would make up the whole circle
so the percent of the pie X 360 = the
measure of the central angle.
29% x 360 = 104.4°
17% x 360 = 61.2°
23% x 360 =82.8°
