How do you rearrange the attached formula to make G the subject?

I'll do the first few steps and you try and finish. OK?

T=2{\pi}\sqrt{\frac{L}{G}}

Divide by 2Pi:

\frac{T}{2\pi}=\sqrt{\frac{L}{G}}

Square both sides to eliminate the radical:

\frac{T^{2}}{4{\pi}^{2}}=\frac{L}{G}