The correct answer is A and B because if you replace the m's with 4 than you do get the answer at the end of the equation. Hope this helps.
Well there both even numbers so the gcf factor would have to be even also
60 = 1,2,3,4,5,6,10,12,15,20,30,60
72 = 1,2,3,4,6,8,9,12,18,24,36,72
The Gcf would be 12
SA = 2
+2

1. Find the radius.
R = 1/2D
6 x 1/2 = 3
R = 3
2. Plug them in.
SA 2(3.14)(3)(7) + 2(3.14)(3^2)
3. Solve
3 x 7 = 21
21 x 3.14 = 65.94
65.94 x 2 = 131. 88
3^2 = 9
9 x 3.14 = 28.26
28.26 x 2 = 56.52
4. Add them together.
131.88 + 56.52 = 188.4
Answer: 188.4 square millimeters
The values go up by 2. So your answer would be 20.