This fundamental theorem of statics simplifies the calculation of torque or moments. Instead of finding the perpendicular distance from a pivot to a complex resultant force, engineers resolve the force into orthogonal components. They then sum the moments of these individual components about the same point, yielding the exact same total moment.
Heard on the job
Use Varignon's theorem to break that angled load into X and Y components before you calculate the moment on the bracket.
Insider tip
It is especially useful when dealing with 3D force vectors where calculating perpendicular lever arms directly is mathematically tedious.