Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Geometry

Question:

D and E are points on the sides. AB and AC respectively of ΔABC such that DE is parallel to BC and AD : DB = 2 : 3. CD and BE intersect each other at F. Then the ratio of the area of ΔDEF and ΔCBF is :

Options:

4 : 25

4 : 9

16 : 25

9 : 25

Correct Answer:

4 : 25

Explanation:

ΔADE ∼ ΔABC

\(\frac{AD}{DE}\) = \(\frac{AB}{BC}\) ⇒ \(\frac{2}{DE}\) = \(\frac{2+3}{BC}\)

                            ⇒ \(\frac{DE}{BC}\) = \(\frac{2}{5}\) 

ΔDEF ∼ ΔCBF

\(\frac{Area\;of\;ΔDEF}{Area\;of\;ΔCBF}\) = \(\frac{DE^2}{BC^2}\) = \(\frac{(2)^2}{(5)^2}\) = \(\frac{4}{25}\)

Req. Ratio = 4 : 25