If you simply square the expression on the right hand side of your equation
you should get the answer quite easily.
The reason why you are probably asked to find T^2 is because....
If you notice there are alot of variables that are not raised to an integer power. In order to make the expression look more "pretty" it is better to write our variables in terms of integer powers as opposed to something raised to the 3/2 power or the square root.
I.E. sometimes its more conveinant to write a^2 = b rahter than a = sqrt(b)