Answer:
T^2*g / 4pi^2 = l
Step-by-step explanation:
T = 2 * pi * sqrt( l/g)
We need to solve for l
Divide each side by 2pi
T/ (2pi) = 2 * pi/2pi * sqrt( l/g)
T/ (2pi) = sqrt( l/g)
Now square each side
(T/ (2pi))^2 = ( sqrt( l/g))^2
T^2 / 4pi^2 = l/g
Multiply each side by g
T^2 / 4pi^2 * g= l/g*g
T^2*g / 4pi^2 = l