A collection of three worksheets on the following topics:

* Sum of angles in a triangle: a worksheet on evaluating the third angle in a triangle given the other two using the fact that their sum is 180 degrees

* Exterior Angles of a Triangle: a worksheet on the exterior angles of a triangle. The exercises require to use the fact that an exterior angle of a triangle is equal to the sum of the two interior opposite angles. 

* Interior and exterior angles in regular polygons: a worksheet on calculate the interior and exterior angle sum of regular polygons and the measure of each interior and each exterior angle of regular polygons.

Detailed solutions are provided.