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Home > CC4 > Chapter 1 > Lesson 1.2.1 > Problem 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.

  1. diagram a

    : Corresponding angle with , so  .
    : and are vertical angles, so they have equal measures. Therefore, .
    : and form a pair of supplementary angles, so .

  1. diagram b

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

  1. diagram c

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