Calculating Semi-Major Axis

[titania]

before you tell me that it's (ApR+PeR)/2, I already know that.

I want to know the formula for calculating my semi-major axis (SMa) from my orbital period (T).

Thanks in advance.

 

[Quick_Nick]

http://en.wikipedia.org/wiki/Semi-major_axis#Orbital_period
Algebra and a knowledge of your planet.