If I plot values of T^4 against d I obtain a straight lined gradient with an intercept.

I need to rearrange the following equation into the y=mx +c form where y =T^4 and x = d. K is a constant.

T^4 = 4pi^4 L K /g^2 - 8pi^4 Ld/g^2

If I identify m and c I can find values for K and g.