1:3, Because you can simplify the numbers by dividing by two.
1 = 1 x 10 exponent 0
27.5 = 2.75 x 10 exponent 1
I hope this helps you
s=2.r.h
r=s/2h
The diameter of the circle is needed. But to solve, you would simply multiply the diameter of the circle by pi (3.14).