Class 6 • Mathematics • Chapter 12
Ratio and Proportion
Learn how to compare quantities using ratios, identify equivalent ratios and solve simple proportion and unitary-method problems.
Learn the Basics
Important Concepts
Build your understanding step by step.
Ratio
Learn how to compare two quantities using a ratio.
Writing Ratios
Understand how ratios are written using numbers and the colon symbol.
Equivalent Ratios
Learn how multiplying or dividing both terms by the same number creates an equivalent ratio.
Simplest Form
Reduce a ratio to its simplest form using common factors.
Proportion
Understand when two ratios are equal and form a proportion.
Unitary Method
Use the value of one unit to solve simple quantity problems.
Quick Guide
Ratio Rules
Ratio
a : b
Compares two quantities of the same kind.
Equivalent Ratio
a : b = ka : kb
Multiply both terms by the same non-zero number.
Proportion
a : b = c : d
Two ratios are equal.
Understand with Examples
Worked Examples
Simplifying a Ratio
Example
15 : 20
Divide both by 5 → 3 : 4
Equivalent Ratios
Example
3 : 5
× 2 → 6 : 10
Unitary Method
5 notebooks = ₹100
1 notebook = ₹20
7 notebooks = ₹140
Visual Learning
Understanding 2 : 3
A ratio of 2 : 3 means that for every 2 units of the first quantity, there are 3 units of the second quantity.
First quantity = 2
Second quantity = 3
Quick Notes
Remember These Points
- • A ratio compares two quantities of the same kind.
- • The order of quantities in a ratio is important.
- • Equivalent ratios have the same value.
- • A ratio should be reduced to its simplest form when required.
- • In the unitary method, first find the value of one unit.
Practice
Practice Questions
Write the ratio of 8 boys to 12 girls in simplest form.
Express the ratio 15:20 in its simplest form.
Find an equivalent ratio for 3:5.
Check whether 2:3 and 8:12 are equivalent ratios.
If 5 notebooks cost ₹100, find the cost of one notebook.
If 1 pen costs ₹12, find the cost of 7 pens.
Test Yourself
Revise ratios, equivalent ratios, proportions and the unitary method before taking the quiz.