An isosceles triangle has perimeter 30 cm and each of the equal sides is 12 cm. Find the area of the triangle. - Mathematics

An isosceles triangle has perimeter 30 cm and each of the equal sides is 12 cm. Find the area of the triangle.

Solution

Let the third side of this triangle be x.

Perimeter of triangle = 30 cm

12 cm + 12 cm + x = 30 cm

x = 6 cm

s="Perimeter of triangle"/2=30/2=15 cm

By Heron's formula,

"Area of triangle "=sqrt(s(s-a)(s-b)(s-c))

=[sqrt(15(15-12)(15-12)(15-6))]cm^2

=[sqrt(15(3)(3)(9))]

=9sqrt15 cm^2

Concept: Area of a Triangle by Heron's Formula
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APPEARS IN

NCERT Class 9 Maths
Chapter 12 Heron's Formula
Exercise 12.1 | Q 6 | Page 203