We use the formula to find the sum of the interior angles of an octagon, then we can divide it by the number of sides it has.

Where 'n' is the number of sides.
An octagon has 8 sides, so we have:

Subtract:

Multiply:

This is the sum of all the angles in a regular octagon, and since an octagon has 8 angles, we divide by 8 to find the measure of one angle.
