Look at the information below from the Math Box in Lesson 8.3.2.
How are the angles in the diagram similar to the angles in the example?
Because all the angles add up to 180°, you can set up the equation:
x + x + x + x + 60° = 180°
Combine like terms:
4x + 60° = 180°
Solve for x.
x = 30°