∆ABC is similar to ∆RST. If the ratio of altitudes of ∆ABC : ∆RST is 1 :4 and if RS = 6 cm, then find the length of AB.

Correct option is C

The side ratio of two similar triangles is always equal.
Given, ∆ABC ~ ∆RST

​$$\frac{AB}{RS} = \frac{AC}{RT} = \frac{BC}{ST}$$

$$\frac{AB}{6} = \frac{1}{4}$$

$$AB = 6 \times \frac{1}{4} = 1.5$$

$$\therefore AB = 1.5$$​​​​​