# Find the area of a triangle whose sides are 3 cm, 4 cm and 5 cm respectively. - Mathematics

Short Note

Find the area of a triangle whose sides are 3 cm, 4 cm and 5 cm respectively.

#### Solution

The area of a triangle having sides aband s as semi-perimeter is given by,

A = sqrt( s(s-a)(s-b)(s-c), where

s = (a+b+c)/2
Therefore the area of a triangle, say having sides 3 cm, 4 cm and 5 cm is given by

a = 3 cm ; b = 4 cm ; c = 5 cm

s = (a+b+c)/2

s = (3+4+5)/2

s =12/2

s = 6 cm Now, area A = sqrt(s(s-a)(s-b)(s-c)

$= \sqrt{6(6 - 3)(6 - 4)(6 - 5)}$
$= \sqrt{6 \times 3 \times 2 \times 1}$
$= \sqrt{36}$
$= 6 c m^2$

Concept: Area of a Triangle by Heron's Formula
Is there an error in this question or solution?

#### APPEARS IN

RD Sharma Mathematics for Class 9
Chapter 17 Heron’s Formula
Exercise 17.3 | Q 2 | Page 24

Share