2D Mensuration

Last Updated : 09 Sep, 2025

2D Mensuration is the branch of mathematics that deals with the measurement of various flat geometric figures and shapes. This includes calculating areas and perimeters of two-dimensional shapes like squares, rectangles, circles, and triangles.

This mathematical discipline primarily involves determining:

Perimeter: The total boundary length of shapes.
Area: The surface coverage of plane figures.

Mensuration Terminologies

Here are the terms you will come across in 2D mensuration. We have provided the term, abbreviation, unit, and definition for easy understanding.

Terms	Abbreviation	Unit	Definition
Area	A	m² or cm²	The surface that the closed form covers is known as the area.
Perimeter	P	cm or m	A perimeter is the length of the continuous line that encircles the specified figure.

Mensuration Formula For 2D Shapes

The following table provides a list of all mensuration formulas for 2D shapes:

Shape	Area (Square units)	Perimeter (units)	Figure
Square	a²	4a	Square dimensions
Rectangle	l × b	2(l + b)	Rectangle dimensions
Circle	πr²	2πr	Circle with radius
Scalene Triangle	√[s(s-a)(s-b)(s-c)], Where, s = (a+b+c)/2	a + b + c	Scalene triangle dimensions
Isosceles Triangle	½ × b × h	2a + b	Equilateral triangle dimensions
Equilateral Triangle	(√3/4) × a²	3a	Equilateral triangle dimensions
Right Angle Triangle	½ × b × h	b + hypotenuse + h	Right Angle Triangle dimensions
Rhombus	½ × d1 × d2	4 × side	Rhombus Diagonals
Parallelograms	b × h	2(l + b)	Parallelogram dimensions
Trapezium	½ h(a + c)	a + b + c + d	Trapezium dimensions