D and E are points on the sides AB and AC respectively of a ΔABC such that DE || BC.

Find the value of x, when

AD = 4 cm, DB = (x - 4) cm, AE = 8 cm and EC = (3x -19) cm.

Given: AD = 4 cm, DB = (x – 4) cm, AE = 8 cm and EC = (3x – 19) cm

By Thale’s theorem,

⇒

⇒ 4(3x – 19) = 8(x – 4)

⇒ 12x – 76 = 8x – 32

⇒ 12x – 8x = 76 – 32

⇒ 4x = 44

⇒ x = 44/4 = 11

Thus, x = 11 cm