What is the formula for finding the sum of the interior angles of a regular polygon?

Find the value of x.

Find the value of x.

Find the measure of the indicated angle.

Find the length of the indicated side.

Find the measure of the indicated angle.

Find the measure of the indicated angle.

How many integer values of x are there so that x, 4, and 11 could be the lengths of the sides of a triangle?

How many integer values of x are there so that x, 18, and 11 could be the lengths of the sides of a triangle?