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Mathematics

The ratio of heights of two triangles is 2 : 3 and the ratio of their areas 3 : 2. The ratio of their bases is :

  1. 1 : 4

  2. 2 : 8

  3. 9 : 4

  4. 4 : 9

Mensuration

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Answer

Let b1 and b2 be the bases of the triangles.

Heights (h1 : h2) = 2 : 3

Areas (A1 : A2) = 3 : 2

Area of a triangle = 12\dfrac{1}{2} × Base × Height

A1A2=12×b1×h112×b2×h232=b1b2×h1h232=b1b2×23b1b2=3×32×2b1b2=94b1:b2=9:4.\Rightarrow \dfrac{A1}{A2} = \dfrac{\dfrac{1}{2} \times b1 × h1}{\dfrac{1}{2} \times b2 × h2} \\[1em] \Rightarrow \dfrac{3}{2} = \dfrac{b1}{b2} \times \dfrac{h1}{h2} \\[1em] \Rightarrow \dfrac{3}{2} = \dfrac{b1}{b2} \times \dfrac{2}{3} \\[1em] \Rightarrow \dfrac{b1}{b2} = \dfrac{3 × 3}{2 × 2} \\[1em] \Rightarrow \dfrac{b1}{b2} = \dfrac{9}{4} \\[1em] \Rightarrow b1 : b2 = 9 : 4.

Hence, option 3 is the correct option.

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