Question

In the fig 6.18, if LM || CB and LN || CD, prove thatAM/MB = AN/AD

PgNo.128 Ques 3 Class 10

Answer 1

(i) In △ ABC, DE∥BC (Given)
∴ AD/DB = AE/EC [By using Basic proportionality theorem]
⇒ 1.5/3 = 1/EC

⇒ Σ EC = 3/1.5

EC = 3×10/15 = 2 cm
Hence, EC = 2 cm

(ii) In △ ABC, DE∥BC (Given)
∴ AD/DB = AE/EC [By using Basic proportionality theorem]
⇒ AD/7.2 = 1.8/5.4
⇒ AD = 1.8×7.2/5.4 = 18/10 × 72/10 × 10/54 = 24/10
⇒ AD = 2.4
Hence, AD = 2.4 cm.

Answer 2

(i) In △ ABC, DE∥BC
   AD/DB = AE/EC
- 1.5/3 = 1/EC

- Σ EC = 3/1.5

EC = 3×10/15 = 2 cm

(ii) In △ ABC, DE∥BC
   AD/DB = AE/EC
- AD/7.2 = 1.8/5.4
- AD = 1.8×7.2/5.4 = 18/10 × 72/10 × 10/54 = 24/10
- AD = 2.4