# What will be the Perimeter of the Triangle? If

If the sides of a triangle are in the ratio of 3:4:5 and its area is 216 sq. cm, then the perimeter of the triangle is

- 80 cm
- 72 cm
- 76 cm
- 84 cm

**Answer: (2) 72 cm**

**Explanation:-
**The ratio of the sides of the triangle = 3: 4: 5

Then, Let the sides of the triangle = 3X, 4X and 5X.

The area of the triangle = 216 sq.cm

Then, 3X x 4X/2 = 216

12 X^{2} = 216 x 2

X^{2} = 216 x 2/12

X^{2} = 36

Square root on both side,

X = 6

Then, the sides of the triangle are 3X = 3 x 6 = 18 cm, 4 X = 4 x 6 = 24 cm, 5X = 5 x 6 = 30 cm

Then, the perimeter of the triangle = 18 + 24 + 30

= 72 cm

Hence, the answer is (2) 72 cm.