This proves that the angles of a triangle must add up to 180 degrees. Back to top. Angles in a complete turn and angles in triangles. A complete turn is a 360˚ rotation.

The triangle angle sum theorem tells us that, given a triangle in flat Euclidean geometry, the sum of the measures of the interior angles is 180 degrees. But our problem doesn’t give us a triangle.

Trigonometry is a branch of mathematics that studies relationships between the sides and angles of triangles. Trigonometry is found all throughout geometry, as every straight-sided shape may be ...