In any case: it can be found according to cosine theorem.
That is, f = √ f12+F2 2+2f1f2cos θ.
θ is the angle between two forces.
For two forces on the same line, we can find them by algebraic sum.
F =F 1+F2
Conventional methods in senior high school physics
Orthogonal decomposition
If in doubt, please ask.
Hope to adopt