Interior Angle

An Interior Angle is an angle inside a shape

interior exterior angles

Here's another example:

interior exterior angles

When we add up the Interior Angle and its corresponding Exterior Angle we get a Straight Angle (180°), making them "Supplementary Angles".

 

interior angles triangle 80 70 30

Interior angles appear in all polygons, from triangles to complex shapes.

The total of a shape’s interior angles depends on its number of sides.

See Interior Angles of Polygons for more info.

 

Interior Angles of Polygons Exterior Angles Supplementary Angles Complementary Angles Angles On a Straight Line Angles Around a Point Degrees (Angle) Geometry Index