Find the measure of an interior and an exterior angle of a regular 46-gon

For any polygon, the formula of the interior angle is 180 - 360/n where n is the number of sides of the polygon. The exterior angle is the supplementary angle of the interior angle. Hence when n is equal to 46, then interior angle is equal to 172.17 degrees and the exterior is equal to 7.83 degrees. 

It should be about 72 square inches because 24 times 3 (.141592) equals 72.