### Home > CCG > Chapter 11 > Lesson 11.1.3 > Problem 11-51

11-51.

Write and solve an equation from the geometric relationships provided in the diagrams below.

Sum of interior angles

Therefore,

You can ultimately solve this problem by factoring.

Note that because the figure is an isosceles triangle, two angles are equal to

and the remaining angle is equal to, since it is supplementary to the angle of .