Can this be solved?.....

Given,

A triangle ABC in which DE is parallel to BC. DC and BE intersect at O such that
area of triangle ADE = 3 sq. units and area of triangle DOE = 1 sq. unit.
Find the area of triangle ABC....

Thinking over the problem since 2 days but m not able to work it out.
Some one help....

6 Answers

30
Ashish Kothari ·

See, we know by mid point theorem,

DE||BC and DE=1/2 BC

Now since, ΔADE and ΔABC are similar,

(DE)2/(BC)2 = arΔADE/arΔABC

Since, DE=1/2 BC,

arΔADE/arΔABC = 1/4

Hence, arΔABC=12 sq units. [1]

36
rahul ·

Absolutely wrong.

I haven't posted D and E to be the mid point of sides AB and AC in my question.

If it was mentioned than why mid point theorem?...

Simply by Similarity property...

DE/BC = AE/AC

=> DE/BC = 1/2
=> Ar(tri. ADE)/Ar(tri.ABC) = DE2/BC2
=> 3/Ar(tri.ABC) = 1/4

=>Ar(tri.ABC) = 12 sq. units..........

·

this is a 2010 kvpy question........
the answer is correct but approach is incorrect

36
rahul ·

Can i get the solution to this question?....

36
rahul ·

Got the solution to this question....

Absolutely not a general solution....

Got it by the resonance solution.....

11
Soham Mukherjee ·

Is it the first step?
ar ADE/ar ABC=ar DOE/ar BOC=DE2/BC2

so,ar ABC=3 ar BOC

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