Question

Literal Equations:
C=2πr solve for r
P=4s solve for s

Answer 1

If you would like to solve the equation C = 2 * π * r for r, you can use the following step:
C = 2 * π * r   /2π
r = C / (2π)

If you would like to solve the equation P = 4 * s for s, you can use the following step:
P = 4 * s   /4
s = P / 4