Question

How many sides does a polygon have if the sum of the measures of its internal angles is five times as large as the sum of the measures of its exterior angles?

• A. $20$
• B. $12$
• C. $15$
• D. $10$

Answer 1

The correct option is B $12$

Sum of measure of Interior angles of a regular polygon is calculated as,
$(n-2)180$ where,
n: Number of sides of a regular polygon.
Sum of exterior angles of a regular polygon always add up to ${360}^o$
$\therefore$ ,$(n-2)180=5\left(360\right)$
$\therefore n=12$