Mathematics Class 6 - Mensuration Notes

Mensuration

Welcome to the chapter on Mensuration for Class 6. In this chapter, you will learn how to measure and calculate the perimeter and area of different shapes. By the end of this chapter, you will be able to solve problems related to length, perimeter, and area confidently!

Introduction

Mensuration is the branch of mathematics that deals with measuring lengths, areas, and volumes of different shapes and objects. It helps us find out how much space a shape covers or how long its boundary is.

Perimeter

The perimeter is the total length of the boundary of a closed figure.

• Rectangle: Perimeter = 2 × (Length + Breadth)
• Square: Perimeter = 4 × Side
• Triangle: Perimeter = Sum of all sides

Example: The perimeter of a rectangle with length 8 cm and breadth 5 cm is 2 × (8 + 5) = 26 cm.

Area

Area is the amount of surface a shape covers. It is measured in square units (like cm², m²).

• Rectangle: Area = Length × Breadth
• Square: Area = Side × Side
• Triangle: Area = ½ × Base × Height

Example: The area of a square with side 6 cm is 6 × 6 = 36 cm².

Units of Measurement

• Length: millimeter (mm), centimeter (cm), meter (m), kilometer (km)
• Area: square centimeter (cm²), square meter (m²)

Word Problems

Use perimeter and area formulas to solve real-life problems. Read the question, identify the shape, and use the correct formula.

• Example: Find the area and perimeter of a rectangle with length 10 m and breadth 4 m.
• Area = 10 × 4 = 40 m²
• Perimeter = 2 × (10 + 4) = 28 m

Fun Activity: Measure and Calculate!

Use a ruler to measure the sides of your notebook. Calculate its perimeter and area.

Summary

• Mensuration helps us measure length, perimeter, and area.
• Use formulas to find perimeter and area of shapes.
• Practice word problems to use mensuration in daily life.

Practice Questions

1. Find the perimeter of a square with side 7 cm.
2. Find the area of a rectangle with length 12 cm and breadth 5 cm.
3. Find the area of a triangle with base 10 cm and height 6 cm.
4. What is the unit for measuring area?
5. Find the perimeter of a rectangle with length 9 m and breadth 3 m.

Challenge Yourself

• Draw a rectangle and label its sides. Calculate its area and perimeter.
• Find the area of your classroom floor using its length and breadth.

Did You Know?

• Mensuration is used in building houses, making gardens, and designing parks!
• The largest area in the world is the Pacific Ocean!

Glossary

• Perimeter: The total length around a shape.
• Area: The surface covered by a shape.
• Unit: Standard measure like cm, m, cm², m².

Answers to Practice Questions

1. 28 cm
2. 60 cm²
3. 30 cm²
4. Square centimeter (cm²), square meter (m²)
5. 24 m

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Practice mensuration every day to become confident in measuring and calculating!