Ratio and Proportion Part -1 Class 10 ICSE

Ratio
A ratio is a comparison of two quantities by division, written as an ordered pair of numbers, such as a/b, where b is not zero. For example, if there are 1 boy and 3 girls, the ratio is 1:3, which means for every one boy there are three girls.
Proportion
A proportion is an equation that sets two ratios equal to each other. For example, a proportion can be written as a:b = c:d or a:b :: c:d.
Here are some more examples of ratios and proportions:
Ratio: "For every 2 apples we have 3 bananas"
Proportion: "There are 50 pieces of fruit, and 1 in every 5 of those is an apple"
You can treat a ratio as a fraction. Two ratios are equivalent if the fractions that correspond to them are equivalent.