### Home > CC3 > Chapter 9 > Lesson 9.1.4 > Problem 9-49

9-49.

Use what you know about the angles in a triangle to find

*x*in each diagram below. Show all work. Then classify each triangle as acute, right, or obtuse. Homework Help ✎

By the Angle Sum Theorem, the sum of all interior angles of a triangle is always 180°.

*x* + 40 + 80 = 180

*x* + 120 = 180

*x* = 60°

(2*x*) + (*x* + 12) + (96) = 180