Mathematics for IGCSE & O level - Geometrical Terms (Section 4 - No. 43)
What is the difference between interior and exterior angles of a polygon?
Interior angles are smaller than exterior angles.
Interior angles are inside the shape, while exterior angles are outside.
Exterior angles are always obtuse.
Interior and exterior angles always add up to 90 degrees.
Explication
Interior angles are inside the polygon, while exterior angles are formed by extending a side.