Mast Rake Formula

cos(R+90) = (Ym^2 + B^2 - X^2) / (2*Ym*B)

R = Rake
Ym = Back of aft coaming to aft of mast at deck
X = Back of aft coaming to aft of mast at step
B = Bury (Deck to seating surface of mast step)