Question

a regular convex polygon has a 140° interior angle. what is the classification of this polygon?

• nonagon

○ heptagon
○ hexagon
○ octagon
○ decagon

Explanation:

Step1: Find exterior angle

The exterior angle is $180^\circ - 140^\circ = 40^\circ$.

Step2: Solve for number of sides

For a regular polygon, sum of exterior angles is $360^\circ$. Let $n$ = number of sides:
$$n = \frac{360^\circ}{40^\circ} = 9$$
A 9-sided polygon is a nonagon.

Answer:

A. Nonagon