JAMB 2014 · UTME · Q25

How many sides has a regular polygon whose interior angles are $135^\circ$ each?

Worked solution (try it first)

An interior angle and its exterior angle add up to $180^\circ$ , so each exterior angle is $180^\circ - 135^\circ = 45^\circ$ .
The exterior angles add up to $360^\circ$ , so the number of sides is $360 \div 45 = 8$ , option A.