Class 7 Mathematics
Chapter 11: Perimeter and Area
STAGE 0: Foundation
Perimeter and area help us measure the boundary and surface of objects.
- Perimeter: Distance around a shape
- Area: Space inside a shape
Examples:
- Fence around a field → Perimeter
- Floor of a room → Area
STAGE 1: Perimeter
The perimeter of a figure is the sum of all its sides.
Perimeter of a Rectangle:
Formula = 2 × (Length + Breadth)
Example:
Length = 6 cm, Breadth = 4 cm
Perimeter = 2 × (6 + 4) = 2 × 10 = 20 cm
STAGE 2: Perimeter of Square
All sides of a square are equal.
Formula:
Perimeter = 4 × side
Example:
Side = 5 cm
Perimeter = 4 × 5 = 20 cm
STAGE 3: Area of Rectangle
Formula:
Area = Length × Breadth
Example:
Length = 8 cm, Breadth = 5 cm
Area = 8 × 5 = 40 cm²
STAGE 4: Area of Square
Formula:
Area = side × side
Example:
Side = 6 cm
Area = 6 × 6 = 36 cm²
STAGE 5: Units of Area
- cm² (square centimetre)
- m² (square metre)
Always write the correct unit while writing the answer.
STAGE 6: Solved Word Problems
Example 1:
Find the perimeter of a square with side 9 cm.
Perimeter = 4 × 9 = 36 cm
Example 2:
Find the area of a rectangle of length 10 cm and breadth 7 cm.
Area = 10 × 7 = 70 cm²
STAGE 7: Practice Questions
1. Find the perimeter of a rectangle with length 12 cm and breadth 8 cm.
2. Find the area of a square with side 7 cm.
3. Find the perimeter of a square with side 15 cm.
4. Write the formula for area of rectangle.
5. Write the formula for perimeter of square.
Shaktimatha CBSE Learning
Class 7 Mathematics – Chapter 11: Perimeter and Area
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