### Home > CCG > Chapter 2 > Lesson 2.3.1 > Problem 2-107

2-107.

*only* those angles that you can justify.

Refer to the Math Notes box in Lesson 2.1.4 or problem 2-41.

The symbols on two of the lines indicate that those lines are parallel.

The angles marked in the diagram below are vertical angles, therefore they are congruent.

The value of can be found because it is supplementary with both

You can also determine the values of angles through

*since they correspond to the angles you have already determined.*