If each angle of a regular polygon measures 150°, how many sides does it have?

Answer 1

If each internal angle of a regular polygon measures 150°, each external angle measures (180-150)=30°.
Since the sum of all polygons add up to 360° and for a regular polygon of n-sides, each exterior angle (E=30°) is equal, we arrive at the relation:
nE=360
n(30)=360
Solve for n.
The name of the polygon starts with the letter 'd'.

Answer 2

Dodecagon