Students use the Triangle Angle-Sum Theorem to solve for the variable in triangles where two or more angle measures are linear algebraic expressions.

This eighth-grade geometry worksheet introduces students to the Triangle Angle Sum Theorem and has them practice finding a missing interior angle in a triangle.

Turn your child into a geometry detective! How many degrees is each missing angle in these quadrilaterals?

How much does your child know about triangles? Can they figure out the missing angle in each of these triangles?