NCERT Class 9 Mathematics Ganita Manjari: Chapter 6 — Measuring Space: Perimeter and Area
This chapter, "Measuring Space: Perimeter and Area," introduces the fundamental concepts of perimeter and area in mathematics. It begins by exploring the idea of perimeter as the total length around the border of a shape, using examples like squares and rectangles. The chapter delves into the calculation of perimeters for various shapes, including the formula for a rectangle (2(a+b)) and a square (4a), highlighting how the square's formula is a special case. It also poses questions about finding the perimeter of a circle and its relation to real-world applications like athletics tracks, setting the stage for understanding how to measure the length around circular paths and its implications in sports.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 9 |
| Subject | Mathematics |
| Book | Ganita Manjari |
| Chapter | Chapter 6 — Measuring Space: Perimeter and Area |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 3 minutes |
| Word count | 520 |
Learning outcomes
- Define and calculate the perimeter of basic shapes like squares and rectangles.
- Understand the concept of perimeter as the total distance around a shape's border.
- Recognize the relationship between the side length and perimeter of a square.
- Begin to explore the concept of measuring the length around a circle.
Vocabulary
| Word | Meaning |
|---|---|
| Perimeter | The total length around the border of a shape. |
| Stagger | The distance between the starting points of adjacent lanes in a race track. |
| Border | The edge or boundary of a shape. |
| Equilateral triangle | A triangle with all sides of equal length. |
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Practice questions
- What is the perimeter of a square with a side length of 5 units? Answer: 20 units (4 * 5).
- What is the perimeter of a rectangle with length 7 units and width 3 units? Answer: 20 units (2 * (7 + 3)).
- If the side of a square is doubled, what happens to its perimeter? Answer: The perimeter also doubles.
Frequently asked questions
What is the perimeter of a shape?
The perimeter of a shape is the total length around its border.
What is the formula for the perimeter of a rectangle?
The perimeter of a rectangle with length 'a' and width 'b' is 2(a + b) units.
What is the perimeter of a square with side 'a' units?
The perimeter of a square with side 'a' units is 4a units.
What is a 'stagger' in a relay race?
A stagger is the distance between the starting points of adjacent lanes in a race, ensuring fair competition.
What happens to the perimeter of a square if its side length is doubled?
If the side of a square is doubled, its perimeter also doubles.
Related resources
Important topics
Topics covered
NCERT Class 9 Mathematics — Ganita Manjari — Chapter 6 — Measuring Space: Perimeter and Area. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.