Polygon of force
This topic just builds on the previous Triangle of Forces.
Consider three forces A, B and C. A and B can be added by drawing a triangle to give a resultant.
If force C is joined to this resultant, a further or "new" resultant is created, which represents the effect of all three forces.
Now this procedure can be repeated many times; the effect is to produce a Polygon of Forces.
Again, the resultant can be derived mathematically.