• Proportion is a comparison between two different quantities of units and is usually expressed as one quantity per unit of another quantity.
• Proportion can be found by dividing the two quantities involved.
• The unit of rate measurement is the unit of numerator per unit of the denominator.

EXAMPLE:
A car can travel 350 km with 50 litres of petrol. How far would it be if the car was only filled with 20 litres of petrol?

SOLUTION:
50 litre = 350 km
20 litre = ____ km
\({\frac{350}{50}}\times20=140 \text{ km}\)