For only the rectangle (that I've coloured in with red) I assume it would be 9 inches squared. However, when adding on the triangles on the side, it would be 9+3+3 = 15
1/3times3=3/3 3/3 is the same as a whole so do 41 and 1/2 times 3 this gets you an answer of 124.5 meaning the unit 124.5x he makes 124.5 rotations per minute