Practicing Success
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 : |
4 : 25 4 : 9 16 : 25 9 : 25 |
4 : 25 |
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 |