Question:
Tick (✓) the correct answer:
Each interior angle of a polygon is 108°. How many sides does it have?
(a) 8
(b) 6
(c) 5
(d) 7
Solution:
(c) 5
Each interior angle for a regular $n$-sided polygon $=180-\left(\frac{360}{n}\right)$
$180-\left(\frac{360}{n}\right)=108$
$\Rightarrow\left(\frac{360}{n}\right)=72$
$\Rightarrow n=\frac{360}{72}=5$