Question

what is the measure of each angle in a regular nonagon?

Explanation:

Step1: Find sum of interior angles

The formula for the sum of interior angles of an $n$-sided polygon is $(n-2)\times180^\circ$. For a nonagon, $n=9$.
$$(9-2)\times180^\circ = 7\times180^\circ = 1260^\circ$$

Step2: Calculate each interior angle

In a regular polygon, all interior angles are equal. Divide the total sum by the number of angles ($n=9$).
$$\frac{1260^\circ}{9} = 140^\circ$$

Answer:

$140$