Question

1. The sides of a triangle are in the ratio 4:5:7. If perimeter of the triangle is 32 cm. Find the area
of the triangle.

Answer 1

Answer:

Given;-

perimeter=36

let the ratio be x

therefore,

⇒AB+BC+CA=36

⇒3x+4x+5x=36

⇒12x=36

⇒x=1236⇒x=3

Now, putting the value of x

AB=3x=9cm

BC=4x=12cm

AC=5x=15cm

On using Pythagoras theorem

AC2=AB2+BC2=(9)2+(12)2=81+144AC2=225AC=15cm

ΔABC is right angled triangle ∠B is right angle.

Area of ΔABC=21AB×BC=21×9×12=54cm2

hence,

Area of triangle is 54cm2