How would i go about tranposing this equation so that I end up with a value for x? Please include working. Thankyou

315.414=2πx^2+860.16/x

first, multiply by x and you get

315.414x = 2πx^3 + 860.16

then rearrange in descending order of exponent:

2πx^3 - 315.414x + 860.16 = 0

Now you have to solve a cubic, which is generally not easy. And in this case, I guarantee it is not easy.

You will have to fall back on graphical or numeric methods to arrive at the solution. See

http://www.wolframalpha.com/input/?i=solve+315.414%3D2%CF%80x^2%2B860.16%2Fx