Question

If △ABC ∼ △DEF such that 2AB = DE and BC = 6 cm, find EF

Answer 1

When two triangles are similar, then the ratios of the lengths of their corresponding sides are equal.
Here, △ABC ∼ △DEF
$$\begin{gathered} \therefore \frac{\mathrm{AB}}{\mathrm{DE}}=\frac{\mathrm{BC}}{\mathrm{EF}} \\ \Rightarrow \frac{\mathrm{AB}}{2\mathrm{AB}}=\frac{6}{\mathrm{EF}} \\ \Rightarrow \mathrm{EF}=12\mathrm{cm} \end{gathered}$$