Question

an isosceles triangle has perimeter 30cm and each of the equal sides is 12cm find the area of the triangle ​

Answer 1

Step-by-step explanation:

perimeter of the triangle=sum of all sides

30cm=AB+AC+ BC 30cm=12cm+12cm+BC [∆ABC is isosceles triangle]

30cm-24cm=BC

6cm=BC

area of triangle=using heron's formula

$\sqrt{s(s - a)(s - b)(s - c)}$

s=AB+AC +CB/2

s=12+12+6/2=15cm

put the value

√15(15-12)(15-12)(15-6)

$\sqrt{3 \times 5 \times 3 \times 3 \times 3 \times 3}$

a

=.

=9√15 (ANS)

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 !