Question

The sizes of seven of the exterior angles of an octagon are

42°, 110°, 130, 67°, 55°, 11° and 53º.
Work out the size of each of the eight interior angles.

Answer 1

Below in bold.

Explanation:

The exterior angles add up to 360,

so the 8th exterior angle = 30 - (42+110+13+67+55+11+53)

= 9 degrees.

Interior angle = 180 - exterior, so in order the interior angles are:

138, 70, 167, 113, 125, 169, 127 and 171 degrees.