### Perimeter and Area - Revision Notes

CBSE Class–VII Subject Mathematics

Revision Notes

Chapter –11

Perimeter and Area

Perimeter is the distance around a closed figure whereas area is the part of plane occupied by the closed figure.- Area is the measure of the part of plane or region enclosed by it.
- We have learnt how to find perimeter and area of a square and rectangle in the earlier class. They are:

(a) Perimeter of a square = 4 × side

(b) Perimeter of a rectangle = 2 × (length + breadth)

(c) Area of a square = side × side

(d) Area of a rectangle = length × breadth - Area of a parallelogram = base × height
- Area of a triangle = (area of the parallelogram generated from it)
- Area of equilateral triangle =
- The distance around a circular region is known as its circumference.
- The ratio of circumference and diameter of a circle is a constant is denoted by (pi).
- Circumference of a circle = πd, where d is the diameter of a circle and (approximately).
- Area of a circle, where r is the radius of the circle.
- Based on the conversion of units for lengths, studied earlier, the units of areas can also be converted: