Algebraic Proportion

Algebraic Proportion

A proportion can be written as a formula. The formula will consist of two variables and a constant. The constant k is the multiplier to one of the variables:

y = kx

Example 1

Write a conversion for a currency conversion from Euros to British Pounds. The conversion rate is 1.2 Euros for every British Pound.

Check that the conversion is correct: for £1, you would expect more Euros.

Answer: p = 1.2e

Example 2

A formula is shown as x = 0.25y. Rewrite this direct proportion to make y the subject.

Multiply both sides of the proportion by 4.

Answer: 4x = y