Page 40 - Math Course 2 (Book 2)

Lines and Angles

Line and Angle Relationships

Parallel Lines Perpendicular Lines Vertical Angle
n

2
1 3
m 4
a
b

∠1 ≅ ∠3
a || b m ⟂ n
∠2 ≅ ∠4
Adjacent Angles Complementary Angles Supplementary Angles
C

D

1
2 2 1 2
A 1
B

m∠ABC = m∠1 + m∠2 m∠1 + m∠2 = 90° m∠1 + m∠2 = 180°

Let’s Begin

Find Measures of Angles

Example

In the figure, m || n and t is a transversal. m n
If m∠7 = 123°, find m∠2 and m∠8.

Since ∠7 and ∠2 are alternate exterior angles, they
are congruent. So, m∠2 = 123°.

1
Answer m∠2 = 123° 3
7 5

Since ∠7 and ∠8 are corresponding angles, they 4 2
are congruent. So, m∠8 = 123°. 8
6

Answer m∠8 = 123°

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