arms of the balance scale are not the same length.
Principle of Moments is expressed by w1d2
= w2d1. The weights of the objects
are inversely proportional to the lengths of the arms of the scale.
Using x for the weight of the cone results in two equations:
w1d2 = xd1
xd2 = w2d1
Multiplying left and right sides gives
x2d1d2 = w1w2d1d2
w1= 4 and w2 = 9, x = ,
or x = 6 and the cylinder weighs 6 pounds.