We already know the following facts about polygons:
The interior angles of a regular polygon are each 120°. Calculate the number of sides.
The interior angles are 120°, so the exterior angles are 180° - 120° = 60°. The exterior angles add up to 360°, so if we divide 360° by 60° we find there are 6 exterior angles. Therefore, there are 6 sides (it is a hexagon).
Try this one:
The interior angles of a regular polygon are each 150°. Calculate the number of sides.
Did you get the answer 12? If so - well done!
If not, remember that the exterior angles are each 30° (180° - 150°).
360 ÷ 30 = 12, so there are 12 exterior angles, and 12 sides.
Now try a Test Bite