Proportional refers to a relationship between two varying quantities where pairs of values always maintain the same ratio between them. If two amounts are proportional, they change at the same rate so that the relationship between them does not change. In mathematics, proportion is a comparison between two numbers, and if two sets of given numbers are increasing or decreasing in the same ratio, then the ratios are said to be directly proportional to each other.

For example, if the speed of a car is increased, it covers more distance in a fixed amount of time, and this is a direct proportion. Another example of proportion is when a ropes length and weight are in proportion, and when 20m of rope weighs 1kg, then 40m of that rope weighs 2kg, and 200m of that rope weighs 10kg, etc. .