Page 153 - Math Course 3 (Book 2)

Circles: Angles and Arcs
Mo. 11

Lesson 2 minor arc

an arc that measures less than 180°.

A
KEY CONCEPTS:

1. Recognize major arcs, minor arcs, AC
semicircles, and central angles and 1100
their measures. C
2. Find arc length.
B

MO. 11 - L2a

Central Angles and Arcs of a major arc
Circle an arc that measures greater than 180°.

D

Vocabulary A-Z E DFE
Let us learn some vocabulary 600

central angle G
A central angle has the center of the circle as its
vertex, and its sides contain two radii of the circle. F

semicircle
1 an arc that measures 180°.

2 3 JKL
J K

arc
A central angle separates the circle into two parts, N
each of which is an arc. The measure of each arc is
related to the measure of its central angle. M L
JML
A
Key Concept

C Sum of Central Angles
B Words The sum of the measure of the central
angles of a circle with no interior points
in common is 360.

Example: m∠1 + m∠2 + m∠3 = 360 1

2 3

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