Question

The perimeter of two similar triangles are 30 cm and 20 cm respectively.If one side of the first triangle is 9 cm long, Find the length of the corresponding side of the second triangle.​

Answer 1

Answer:

We know that If a/d = b/e = c/f then

each ratio = (a+b+c)/(d+e+f)………….(1)

This concept is used to solve the given problem.

We also know that if two triangles say, ABC and DEF are similar, then the corresponding sides are proportional.

So, if ∆ABC ~ ∆ DEF then

AB/DE = BC/EF= AC/DF

Suppose AB = 15, Also given,

perimeter of ∆ABC/ perimeter of ∆ DEF = 30/20 = 3/2

i.e., (AB+BC+CA)/(DE+EF+DF) = 3/2

Applying (1) AB/DE = 3/2 => 15/DE = 3/2

=> DE = 10 cm