Question

The sides of a triangle are in the ratio 3 : 4 : 5. If the perimeter of the triangle is 84 cm, then area
of the triangle is

Answer 1

Step-by-step explanation:

Let the sides of the triangle= x

it will become = 3x , 4x and 5x

PERIMETER OF TRIANGLE= SUM OF ALL SIDES.

3x+4x+5x = 84

12x=84

x=84/12

x= 7

sides = 3*7=21, 4*7=28 and 5*7=35

AREA OF TRIANGLE=1/2*B*H

Answer 2

Answer:

294 cm²

Step-by-step explanation:

Let the common ratio be x.

1st side= 3x

2nd side = 4x

3rd side = 5x

3x+4x+5x=84 (Perimeter)

12x=84

x=84/12

x= 7

1st side =AB = 7*3=21

2nd side =BC 7*4=28

3rd side =AC 7*5 = 35

By heron's formula

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

where s=a+b+c/2

s=21+28+35/2 = 84/2

s=42

area = $\sqrt{42(21*14*7)}$

area = 294 cm² Ans.