We want to find the sum of the interior angle measures of the given regular polygon.
Recall that the measure of each interior angle of a regular n -gon is ( n-2)180 n. To find the measure of an interior angle of a 15 -gon, we have to substitute 15 for n in this expression.
( 15-2)180/15= 156
Because there are 15 sides, there are 15 angles. We can multiply this angle measurement by 15 to find the sum of the angles.
156 * 15 =2340
