# The Sides of a Triangle Are 7 Cm, 9 Cm and 14 Cm. Its Area is - Mathematics

MCQ

The sides of a triangle are 7 cm, 9 cm and 14 cm. Its area is

#### Options

• $12\sqrt{5} c m^2$

• $12\sqrt{3} c m^2$

• $24\sqrt{5} c m^2$

• $63 c m^2$

#### 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 having sides 7 cm, 9 cm and 14 cm is given by

a = 7 cm ; b = 9 cm ; c = 14 cm

s = (a+b+c)/2

s = (7+9+14)/2

s = 30/2

s = 15 cm

A = sqrt(15(15-7)(15-9)(15-14))

A = sqrt(15(8)(6)(1))

A = sqrt(720)

A = 12 sqrt(5)  cm^2

Is there an error in this question or solution?

#### APPEARS IN

RD Sharma Mathematics for Class 9
Chapter 17 Heron’s Formula
Q 3 | Page 24