Question

Two similar triangles have a ratio of 3 in: 5 in. The larger triangle has an perimeter of 120 cm. What is the perimeter of the smaller triangle?

Answer 1

If two triangles are similar, then the ratio of their corresponding sides is constant. The perimeter of a traingle is the sum of the length of each side. This means that the ratio of the perimeter of both triangles is also constant.

Let x represent the perimeter of the smaller triangle. Given that the perimeter of the larger triangle is 120 cm, it means that

3/5 = x/120

By cross multiplying, it becomes

5 * x = 3 * 120

5x = 360

x = 360/5

x = 72

Perimeter of the smaller triangle is 72 cm