CBSE Class 7 Maths Chapter 11 Notes Perimeter and Area

Perimeter and Area Class 7 Notes Conceptual Facts

1. Perimeter is the actual distance around a closed figure.

2. Perimeter of a regular polygon = Number of sides x Length of one side

3. Perimeter of a square = 4 x side

4. Perimeter of a triangle = AB + BC + CA (Sum of all sides of triangle)

5. Perimeter of a rectangle = 2 [length + breadth]
= 2(l+ b)

6. Circumference of a circle is the actual distance around it.

7. Ratio of the circumference and the diameter of a circle is a constant

8. The numerical value of π is taken as \(\frac{22}{7}\) or 3.14. (approximate)

9. Circumference of a circle = 2πr, where r is the radius of the circle.

10. Area of a rectangle = length x breadth = l x b

11. Area of a triangle = \(\frac{1}{2}\) x base x height = \(\frac{1}{2}\) x b x h

12. Area of circle = πr², where r is the radius of the circle.

13. Area of a parallelogram = base x height

14. Area of a square = (Side)² = l²

Conversion of units