Please help don't guess.

The easy way to do this is:
Since the radius of the second circle is exactly 6 times the radius of the first circle, you could just multiply the circumference by 6:
9.42 x 6 = 56.52! But let's double-check.
9 x 2 = 18 So, the diameter is 18.
18 x 3.14 = 56.52! So, 56.52 is the correct answer!
Remark
The formula you should be using is
C = k*r because this is a variation question. There are ways of doing this without solving for k, but it is a good idea to solve for k first.
Givens
C = 9.42
r = 1.5
k = ??
K =
C = k*r
9.42 = k * 1.5
k = 9.42/1.5
k = 6.28 which is what it should be given that pi = 3.14. But you must check.
r = 9
C = k*r
C = 6.28 * 9
C = 56.52 which rounded = 57 to the nearest inch
57 Answer