Aptitude - Area Calculation


Important Fact and Formulae

Following are important facts and formulaes used in questions for area calculations.


  • Area of a rectangle = Length x Breadth

  • Length of a rectangle = Area / Breadth

  • Breadth of a rectangle = Area / Length

  • Perimeter of a rectangle = 2(Length + Breadth)

  • Area of 4 walls = 2(length+ Breadth) x height

  • Area of a Square = (side)2 = 1/2(diagonal)2


  • Area of a triangle= (1/2 x Base x Height)

  • △ =√{S(S-A) (S-B)(S-C)}, where S=1/2(a+b+c)

  • Area of equilateral triangle = √3/4 x a2

  • Radius of a in circle of an equilateral triangle of side a = a/2√3

  • Radius of a circumcircle of an equilateral triangle of side a =a/√3

  • Radius of in circle of a triangle= △/S, Where s=1/2(a+b+c)


  • Area of a circle= πR2

  • Circumference = 2πR

  • Arc length= 2πRϑ/360, where ϑ is a central angle.

  • Area of Sector=1/2(arc length x R) = πR2ϑ/360

  • Area of Semicircle= 1/2πR2

Other shapes

  • Area of a parallelogram = (base x height)

  • Area of a rhombus= 1/2(product of diagonals)

  • Area of a trapezium= 1/2 (sum of parallel sides) x (distance between them)

Solved Examples

Solved Examples