Answer:

1180°, since the sum of the sides are 90°+90°+90°=180! :) i don't know if they are correct tho but A for effort :)!!

determine the sum of the interior angle

The formula for calculating the sum of interior angles is ( n − 2 ) × 180 ∘ where is the number of sides. All the interior angles in a regular polygon are equal. The formula for calculating the size of an interior angle is: interior angle of a polygon = sum of interior angles ÷ number of sides.