Three cubes of sides 1 cm, 6 cm and 8 cm are melted to form

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Three cubes of sides 1 cm, 6 cm and 8 cm are melted to form a new cube. Find half of the surface area of the new cube. ?

1. 243 sq cm
2. 463 sq cm
3. 486 sq cm
4. 293 sq cm

Correct Option: A

Volume (new cube) = (1³ + 6³ + 8³ ) = 729 cm³
a³ = 729
⇒ a = ∛ 729
∴ Surface area of the new cube = 6a²
= 6 x 9² = 486 sq cm
Surface area/2 = 486/2 = 243 sq cm