Lami's theorem

Lami's theorem is very helpful tool in mechanics to solve various problems that include exactly three vector quantities. 

What is Lami's theorem ?

Lami's theorem states that if three co-planer forces are acting on the same point then each force is proportional to the sine of the angle between other two forces.

Formula
This formula is given as:


Explanation
Consider three forces:
Let OA = F3
OB = F1
OC = F2

Also note that
* Angle opposite to OA is "alpha".
* Angle opposite to OB is "Beta".
* Angle opposite to OC is "Gamma".