constant of variation

Question

Find the constant of variation if x varies inversely as y and x = 3 when y = 10

Answer 1

Two variables are said to be inversely proportional, or inversely related, if their product is constant. The general formula is xy = k, where k is the constant of variation (also called the constant of proportionality). Since the example point given is (3, 10), then k must be the product of those numbers, or 30.