Given DE || BC, AD = 2.4 cm, DB = 3.6 cm and AC = 5 cm.

We have to find AE.

We know that basic proportionality theorem states that if a line is drawn parallel to one side of a triangle to intersect the other two sides in distinct points, then the other two sides are divided in the same ratio.

⇒ 2.4 (5 – AE) = 3.6 AE

⇒ 12 – 2.4 AE = 3.6 AE

⇒ 12 = 3.6 AE + 2.4 AE

⇒ 12 = 6 AE

⇒ AE = 12/6

∴ AE = 2 cm