### Home > CC4 > Chapter 1 > Lesson 1.2.1 > Problem 1-42

1-42.

Recall what you learned about angle relationships in previous courses. (See the Math Notes box in this lesson if you need a reminder.) Determine the measures of the labeled angles. The double arrowheads indicate that the pair of lines is parallel. Homework Help ✎

All three of these can be solved using multiple techniques related to parallel lines.

: Corresponding angle with , so .

: and are vertical angles, so they have equal measures. Therefore, .

: and form a pair of supplementary angles, so .

and form a pair of supplementary angles. How are and related?

Since there are parallel lines, look for relationships between pairs of angles such as alternate interior, corresponding, or same-side interior.