Page 160 - Math Course 3 (Book 2)

Circles: Arcs and Chords
Mo. 11

Lesson 3 THEOREM 11.2

In a circle or in congruent circles, two minor arcs
are congruent if and only if their corresponding
KEY CONCEPTS:
chords are congruent.
1. Recognize and use relationships between
arcs and chords. Abbreviation:
2. Recognize and use relationships between In ⊙, 2 minor arcs are ≅, corr. chords are ≅.
chords and diameters. In ⊙, 2 chords are ≅, corr. minor arcs are ≅.

Examples:
A
If AB ≅ CD, AB ≅ CD.
MO. 11 - L3a B
If AB ≅ CD, AB ≅ CD.
The Relationships Between
Arcs and Chords C
D

Vocabulary A-Z
Let us learn some vocabulary

Let’s Begin
inscribed
A polygon is inscribed if all of its vertices lie on the
circle.
Prove Theorem 11.2
Quadrilateral ABCD is an inscribed polygon
because all of its vertices lie on the circle. Example
A

Proof: Write a two-column proof.
D E B
Given: DE ≅ FG
m∠EBF = 24

C DFG is a semicircle.

circumscribed Prove: m∠FBG = 78
a circle is circumscribed about a polygon if it
contains all the vertices of the polygon. G

Circle E is circumscribed about the polygon F
because it contains all the vertices of the polygon.
A E

B
D E B

D
C
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