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 = 12(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 π=227 or 3.14 (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: