K-method

K-method is used to prove that two different ratios are equal. Each of the given ratio is equated to K. The quantities in ratio are expressed in terms of K, and necessary substitution helps in getting the two sides of the equity. These two sides are in terms of a single variable K, and hence quality can be proved.

Example

If a:b :: c:d, prove that
Using K-method, we can write
We have to prove
Substitute a = bk and c = dk on both sides of the equation

Hence, L.H.S. = R.H.S. = K