In the figure given below, if DE || FG || BC. Find AD : DF : FB?
Explanation:
Let A(∆ADE) = 1, hence A(DEGF) = A(FGCB) = 1
∴ A(∆AFG) = 2 and A(∆ABC) = 3
In the figure, DE || FG || BC, hence ∆ADE is similar to ∆AFG is similar to ∆ABC
Since, the 3 triangles are similar, the ratio of their areas will be same as the ratio of squares of their sides.
⇒ A(∆ADE) : A(∆AFG) : A(∆ABC) = 1 : 2 : 3 = AD2 : AF2 : AB2
⇒ AD : AF : AB = 1 : √2 : √3
Now, DF = AF - AD = √2 - 1 and, FB = AB - AF = √3 - √2
∴ AD : DF : FB = 1 : (√2 - 1) : (√3 - √2)
Hence, option (d).
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