If an object is under effect of 2 forces where there is an alpha angle between them;
If the angle is a good one like 60, 90 or 120; and
Shortcut: If three forces are acting on same object
If three forces are acting on the same object like shown on the picture and if they are in balance;
Then the force opposite to the biggest angle will have the smallest value, the force opposite to the biggest value will have the biggest value.