Question

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

Answer 1

perimeter =30cm
side=12cm
area of triangle =a+b+c\2
=36/2

18cm
√s(s-a)(s-b)(s-c)
36√3

Answer 2

☆ Solution ☆

Given :-

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

To Find :-

The area of the triangle.

Step-by-Step-Explaination :-

Let the third side be x

So,

12 + 12 + x = 30

24 + x = 30

x = 30 - 24

x = 6

Hence,

The length of the third side is 6 cm.

Now,

The semi perimeter of the isosceles triangle (s) = 30/2 cm = 15 cm

By using Heron's Formula,

As we know that :-

Area of triangle = √ s ( s - a ) ( s - b ) ( s- c )

Putting the respective value,

√ 15 ( 15 - 12 ) ( 15 - 12 ) ( 15 - 6 ) cm²

√ 15 × 3 × 3 × 9 cm²

9 √ 15 cm²

Hence Solved !