(Q21) The perimeters of two similar triangles are 30 cm and 20 cm respectively. If one side of the first triangle is 12 cm, determine the corresponding side of the second triangle.

Solution :

Given :∆ABC ∼ ∆PQR

Perimeter of ∆ABC = 30 cm.

Perimeter of ∆PQR = 20 cm.

AB = 12 cm.

Ratio of perimeters = 30 : 20 = :

Let the length of the side corresponding to the side with length 12 cm be x.

Then 30 : 20 :: 12 : x

× x = ×