Parallelogram Law?

Question

When two ropes are attached to a box, how do you figure out the weight of the box if you are given the angle and force in Newtons of the two ropes.

Answer 1

In mathematics, the simplest form of the parallelogram law belongs to elementary geometry. It states that the sum of the squares of the lengths of the four sides of a parallelogram equals the sum of the squares of the lengths of the two diagonals. In case the parallelogram is a rectangle, the two diagonals are of equal lengths and the statement reduces to the Pythagorean theorem. But in general, the square of the length of neither diagonal is the sum of the squares of the lengths of two sides.

PL. VISIT:
http://mathworld.wolfram.com/ParallelogramLaw.html

Answer 2

parellologram law gives the sum of the two sides of a parellologram by the diagonal of it.
suppose:
2 forces are actimng at the same point in different directions.then the resultant of those 2 forses is represented by the diagonal formed such that u start from the starting pt of 1 force
and join the ending pt of 2 force which forms a parellologram.u can construct for a no.of force results by using this law.
as u ask,this law doen"t give the weight of the box,just the resultant force of the two ropes that"s all.