Question

an isosceles triangle has perimeter 30c.m and each of the equal sides is 12c.m. find the area of the triangle.

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Answer 1

Given :

⬤ Perimeter of Isosceles triangle = 30 cm

⬤ Two equal Sides are = 12 cm

To Find :

⬤ Area of Triangle .

Solution :

Let :

• a = 12 cm and b = 12 cm
• c = x

a + b + c = 30

12 + 12 + x = 30

24 + x = 30

x = 30 - 24

x = 6

Therefore , The Value of x is 6.

Now :

s = a + b + c/2

s = 12 + 12 + 6/2

s = 30/2

s = 15 cm

Therefore , Semi-Perimeter is 15 cm.

So ,

$\sf{Area=\sqrt{s(s-a)\:(s-b)\:(s-c)}}$

√15 (15-12) (15-12) (15-6)

√15 × 3 × 3 × 9

3 × 3 √5 × 3

9√15 cm²

Hence , Area of Triangle is 9√15 cm²