Well D I would think because 52 is greater than the other number :)
Hope this helps ^W^
Answer - to solve for the equivalent equation of r you would need to use the formula r=c/pi2.
I assume you're looking for the number:
0.5n + 9 = 21
- 9
0.5n = 12
÷ 0.5
n = 24
So the beginning number is 24, hope this helps!
Just think of it as normal subtraction. They both have the same denominators all you need to do is subtract. 11/12-7/12 is 4/12 if you simplify which just means to find the number that both 4 and 12 can go into equally the simplified answer would be 1/3. You just need to divide 4 by both the top and the bottom (numerator and denominator).
