The equilateral triangles shown below are similar.
Two equilateral triangles are shown. The triangle on the left has side length measuring 2 cm. The triangle on the right has side length measuring 5 cm.
What is the ratio of their perimeters?
A.
4
25
B.
2
5
C.
4
5
D.
1
1 answer
The perimeter of an equilateral triangle is three times its side length. Therefore, the ratio of the perimeters is equal to the ratio of the side lengths, which is $5/2$. Simplifying this ratio gives $\boxed{\textbf{(C) }4/5}$.