Question

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

Answer 1

perimeter = a+b+c
given ratio = 3:4:5
side a = 3x
side b= 4x
side c = 5x
total = 3x+4x+5x
        =12x
12x = 216cm
x=216/12
  =18
x=18cm

side a = 3*18 =54cm
side b= 4*18 =72cm
side c= 5*18 =90cm

now , area =>
area =1/2*h*b
        =0.5 * 54*72
        =27*72
        =1944cm²

Answer 2

$\bf 1944cm^2$