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Exterior Angles of Polygons

# Exterior Angles of Polygons

### Exterior Angles of Polygons

The exterior angles of polygons are linked to their interior angles, and we can use geometrical rules to find unknown angles between them.

Exterior angles are the angles outside of a 2D shape, and are intrinsically linked with the interior angles.

A **convex** polygon is a 2D shape where all the angles point away from the centre of the shape. A **concave** polygon, conversely, contains at least one angle pointing inwards.

What is the size of of one exterior angle of a regular convex octagon?

If we know the exterior angle, we can work out the number of sides of the polygon by dividing 360 by the exterior angle.

If the exterior angle of a polygon is $60\degree$, how many sides does it have?