Find G in "T = 2pi * sqrt(L/G)"?

Like the title I would like to know the exact steps in trying to finding how to find G in this equation. See were doing this lab on the pendulum and when doing our calculations we have to use the period we got for time and the length of the string as L. Like for instance, I got a period or 1.32 seconds and the length of the string of 42.2 cm. We have to put into the equation and figure out g (m/s). How do you figure that out and can you put the numbers I gave you into a step by step example?