Answer 1

Given: ΔABC and ΔDEF are similar triangles such that 2AB = DE and BC = 8 cm.

To find: EF

We know that if two triangles are similar then there sides are proportional.

Hence, for similar triangles ΔABC and ΔDEF

`(AB)/(DE)=(BC)/(EF)=(CA)/(FD)`

`(AB)/(DE)=(BC)/(EF)`

`1/2=8/(EF)`

`EF= 16cm`
Hence the correct answer is `a`.