RD Sharma Solutions for Class 7 Chapter 9 “Ratio and Proportion”, A ratio is a way to compare two quantities by using division as in miles per hour where we compare miles and hours. A proportion, on the other hand, is an equation that says that two ratios are equivalent. If one number in a proportion is unknown, you can find that number by solving the proportion. It includes the concept students concentrate on the definition of ratio, the ratio in the simplest form, comparison of ratios, equivalent ratios, the definition of proportion and property of mean proportional via examples and verbal problems related to it.