Question: The weight W kg of a metal was varies jointly as it length L meters and square of its diameter d metres if W=140 when d =4 2/3 and L=54 find d in terms of W and L.
The formula is: W = k*L*d^2, where k is the constant of proportionality.
Using the given data,
140 = k*(54)*(4 2/3)^2 = k*54*196/9
k = (9*140)/(54*196) = 5/42
k = 5/42
The formula is: W = (5/42)*L*d^2