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 \( \Large cm^{2} \)

Correct Answer:
B) 216 \( \Large cm^{2} \)

Description for Correct answer:
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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