∆ DEF ~ ∆ ABC. If AB = 4 cm, DE = 3 cm, find the value of [(∆DEF:∆ABC)] = ?

Solution:

∆ DEF ∼ ∆ ABC  [Given]

∆ DEF   = DE2 [Areas of similar triangles] ∆ ABC AB2

∆ DEF   = 32 ∆ ABC 42

∆ DEF   = 9 ∆ ABC 16

Answer: ∆ DEF   = 9 ∆ ABC 16