A cuboid whose sides are 8 cm, 27 cm, and 64 cm is melted to form a new cube. What is the respective ratio of the total surface area of the cuboid and cube?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 307 : 216.
The volume of the cuboid is = l × b × h
⇒ 8 × 27 × 64 = 13824 cm3
The volume of the cube will be equal to the volume of the cuboid.
Hence¸
⇒ s3 = 13824
⇒ s =
⇒ s = 24 cm
The ratio of the total surface area of the cuboid and cube:
⇒ 2(l × b + b × h + h × l) : 6 × s2
⇒ 2(8 × 27 + 27 × 64 + 64 × 8) : 6 × 242 = 2 × 2456 : 6 × 576
⇒ 4912 cm2 : 3456 cm2
⇒ 307 : 216