Question

5. In AABC, D and E are points on AB and AC
respectively such that DE || BC. If AE = 2 cm,
EC = 3 cm and BC = 10 cm, then DE is equal to 4
How??​

Answer 1

Thus, DE divides the two sides AB and AC proportionally.

Thus,AD/AB = AE/AC

Thus, ∆ABC≈∆ADE

AB/AD = AC/AE = BC/DE [C.S.C.T]

Now,

AC/AE = BC/DE

→DE = AE × BC/AC

→DE = 2 × 10/5 [AC = (AE+EC)= 2+3=5]

→DE= 4cm