Jon S. answered 04/27/21
Patient and Knowledgeable Math and English Tutor
Top angle of triangle is 360/12 = 30 degrees, so bottom right angle is 60 degrees and we have a 30-60-90 right triangle. Side opposite 30 degree angle is 9 feet (half the length of the full side, so side opposite 60 degree angle (the apothem) is 9sqrt(3) feet. Perimeter is 18*6 - 108 feet. Area is 1/2*apothem * perimeter.