In a triangle ABC, DE parallel BC if AD: DB 3.5, then find ar(triangleDEF)÷ar(triangle CFB)

In a triangle ABC, DE parallel BC if AD: DB 3.5, then find ar(triangle

1.	In a triangle ABC, DE parallel BC if AD: DB 3.5, then find ar(triangleDEF)÷ar(triangle CFB)
Answer» F should be replaced by A bcoz there\'s no F in Δ ΔABC~ΔADE..... (by SAS similarity)......... Now by theorem 6.6, ar(ΔABC)/ar(ΔADE)=(AB/AD)^2...........So ar(ΔABC)/ar(ΔADE)=(3/5)^2 = 9/25...