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# Three cubes whose edges measure 3 cm, 4cm and 5cm respectively are melted to form a new cube. The surface area of the new cube is

 A) 50 $$\Large m^{2}$$ B) 216 $$\Large cm^{2}$$ C) 250 $$\Large cm^{2}$$ D) 300 $$\Large cm^{2}$$

 B) 216 $$\Large cm^{2}$$

If a is side of the new cube, then

$$\Large a^{3}= \left(3^{3}+4^{3}+5^{3}\right)$$

$$\Large = 27 + 64 + 125$$

= $$\Large 216 = 6^{3}$$

Therefore, a = 6 cm

Surface area of the new cube

=$$\Large 6a^{2} = 6 \times 6^{2}$$

=$$\Large 216\ cm^{2}$$

Part of solved Mensuration questions and answers : >> Aptitude >> Mensuration

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