KTUYSBeta
Log inSign up

Triangles · Class 10 · CBSE Mathematics

In a triangle ABC, D and E are points on the sides AB and AC respectively such that DE parallel BC. If AD = 2 cm, DB = 3 cm, and BC = 7.5 cm, find th…

Practice question from Triangles (Class 10 · CBSE Mathematics), with the correct answer and a step-by-step solution.

medium · MCQ · Q-4DB354

In a △ABC\triangle ABC, DD and EE are points on the sides ABAB and ACAC respectively such that DE∥BCDE \parallel BC. If AD=2AD = 2 cm, DB=3DB = 3 cm, and BC=7.5BC = 7.5 cm, find the length of DEDE.

  1. A.2.52.5 cm
  2. B.33 cmCorrect answer
  3. C.4.54.5 cm
  4. D.55 cm

Solution

Since DE∥BCDE \parallel BC, △ADE∼△ABC\triangle ADE \sim \triangle ABC. Therefore, ADAB=DEBC\frac{AD}{AB} = \frac{DE}{BC}. Given AD=2AD = 2, DB=3DB = 3, so AB=5AB = 5. Thus, 25=DE7.5\frac{2}{5} = \frac{DE}{7.5}, which gives DE=2×7.55=3DE = \frac{2 \times 7.5}{5} = 3 cm.

More from Triangles

All of Triangles

Practise more Mathematics

Sign up free for adaptive practice on this chapter, with instant feedback and hints on every question.

Start practising free

Free to start · No credit card needed