1. In a triangle, two angles measure 50° and 60°. What is the third angle?
The interior angles of any triangle sum to 180°. Subtract the known angles: 180° − (50° + 60°) = 180° − 110° = 70°. This follows directly from the Triangle Angle Sum Theorem.
∠C = 180° − (50° + 60°) = 70°