Varignon theorem

One of the fundamental theorems in the theory of sliding vectors (cf. Vector). According to Varignon's theorem, if a system of sliding vectors can be reduced to a single resultant , the moment of the resultant about some point 0 (or axis ) is equal to the sum of the moments of the vectors constituting the system about this point (or axis):

Established in 1687 by P. Varignon for a convergent system of forces. The theorem is extensively employed in geometrical statics, kinematics of rigid bodies and strength of materials.