Given: ∆ABC ∼ ∆DEF

2AB = DE ……….(i)

BC = 6 cm

To find: EF

∵ ∆ABC ∼ ∆DEF

∴ Ratio of all the corresponding sides of ∆ ABC and ∆ DEF are equal.

……….(ii)

Also, from (i), we have

2AB = DE

……….(iii)

[By (ii) and (iii)]