3.4. Alternate Interior Angles http://www.ck12.org
m^62 = 115 ◦because they are corresponding angles and the lines are parallel.^6 1 and^6 2 are vertical angles, so
m^61 = 115 ◦also.
(^6) 1 and the 115◦angle are alternate interior angles.
Example B
Find the measure of the angle andx.
The two given angles are alternate interior angles so, they are equal. Set the two expressions equal to each other and
solve forx.
( 4 x− 10 )◦= 58 ◦
4 x= 68 ◦
x= 17 ◦
Example C
Prove the Converse of the Alternate Interior Angles Theorem.