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in Surface Areas And Volumes by (29.9k points)
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Two cubes have their volumes in the ratio 1 : 27. The ratio of their surface areas is 

A. 1 : 3 

B. 1 : 9 

C. 1 : 27 

D. None of these

1 Answer

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Best answer

Given that, 

Volumes are in the ration 1: 27 

Therefore,

\(\frac{Volume1}{Volume2}=\frac{1}{27}=\frac{a^3}{b^3}\)

a = \(\frac{b}{\sqrt[3]27}\)

a = \(\frac{b}{3}\)

Or b = 3a

Or \(\frac{b}{a}=3\)

We have to find out ratio of their surface areas:

\(\frac{Surface\,area\,1}{Surface\,area\,2}=\frac{6a^2}{6b^2}\)

\(\frac{a^2}{b^2}\)

\(\frac{(\frac{b}{3}^2)}{b^2}\)

\(\frac{1}{9}\)

Therefore, the surface areas are in the ratio 1: 9 

Hence, option B is correct

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