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.

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

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