CBSE Class 8 Mathematics Worksheet - Direct and Inverse Proportion

CBSE Class 8 Mathematics Worksheet 

Direct and Inverse Proportion

Introduction

Direct and inverse proportion are two types of relationships between two quantities. Understanding these concepts is essential for problem-solving in mathematics and real-life situations.

Direct Proportion

A direct proportion is a relationship between two quantities where one quantity increases or decreases in direct proportion to the other. If two quantities are in direct proportion, then their ratio remains constant.

Key Points

- If two quantities are in direct proportion, then as one quantity increases, the other also increases.

- The ratio of the two quantities remains constant.

- Direct proportion is represented by the symbol '∝'.

Formula

If two quantities 'x' and 'y' are in direct proportion, then:

x ∝ y

This can be written as:

x = ky

where 'k' is the constant of proportionality.

Inverse Proportion

An inverse proportion is a relationship between two quantities where one quantity increases or decreases in inverse proportion to the other. If two quantities are in inverse proportion, then their product remains constant.

Key Points

- If two quantities are in inverse proportion, then as one quantity increases, the other decreases.

- The product of the two quantities remains constant.

- Inverse proportion is represented by the symbol '∝ 1/'.

Formula

If two quantities 'x' and 'y' are in inverse proportion, then:

x ∝ 1/y

This can be written as:

xy = k

where 'k' is the constant of proportionality.

Solved Examples

Practice Questions

1. If x and y are in direct proportion, and x = 6 when y = 3, then find the value of y when x = 8.

2. If x and y are in inverse proportion, and x = 4 when y = 6, then find the value of x when y = 3.

Tips and Tricks

- dentify whether the problem involves direct or inverse proportion.

- Use the formula for direct or inverse proportion to solve the problem.

- Check your answer by plugging it back into the formula.

Important Points

- Direct proportion: x ∝ y, x = ky

- Inverse proportion: x ∝ 1/y, xy = k

- Constant of proportionality: k

Worksheet

https://t.me/cgscbsesupportbypramodsir/7