The RD Sharma Solutions for Class 7 Maths Chapter 9 ratio and proportion helps students understand the concept of a ratio and how it is formed. The ratio is a fraction that displays how many times one quantity is higher than the other when they are of the same kind and in the same units. This topic is also about understanding the ratio in the simplest form. A ratio x: y is said to be in the simplest form if it's antecedent 'x' and consequent 'y' have no common factor other than 1. A ratio in the simplest form can also be termed as the ratio in the lowest terms.
The ratio 9: 27 is not in its simplest form, for example, because 9 is a common element of its antecedent and consequent. Therefore, the simplest form is 1:3, and this can be easily done by dividing the 1st and 2nd terms by 9. Meanwhile, while comparing the ratios, the students will learn how to arrange the ratios. The steps on how to make the comparison are as follows. Firstly, make the 2nd term of both the ratios equal. Secondly, compare the numerators (first terms) of the newly formed ratios.
In addition to this, students learn the definition and meaning of equivalent ratios. Equivalent ratios are the ones that make the same comparison of numbers. Here, two ratios can be termed equivalent if one is expressed as a multiple of the other.
On the other hand, students also obtain some knowledge on proportions. A proportion is nothing but the equality of two ratios. In Class 7 Maths Chapter 9, ratio and proportion, students learn the definition of mean proportional. Mean proportionality can also be said as a geometric mean. The term 'mean' can be used alone or in a context, namely mean, median, and mode. This refers to finding the average and is called the arithmetic mean. A geometric mean or mean proportional is not the same as that because the arithmetic mean deals with addition, whereas the geometric one deals with multiplication.