Help me please I don't get it​

I’ll happily do a step by step with you
First, the square in the middle, 4 x 4 = 16, the square is 16 centimeters. Next are the triangles. 6 x 4 = 24, but since a triangle takes up half the space a square would, divide by 2. Each triangle’s surface area is 12, so 12 x 4 = 48. Now, to add it up. 48 + 16 = 64 centimeters squared, which is my final answer.

Answer: r=4.5  feetexplanation: radius  r  is half of the diameter  d,⇒r=d2=92=4.5  feetidk i could be wrong