A right circular solid cylinder has radius of base 7 cm and height is 28 cm. It is melted to form a cuboid such that the ratio of its side is 2 : 3 : 6. What is the total surface area (in cm2) cuboid?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4, i.e. 72(1078/9)2/3
Now, radius of cylinder = 7 cm
height = 28 cm
Volume = πr2h = 22/7 × 7 × 7 × 28
Volume of cylinder = Volume of cuboid
22/7 × 7 × 7 × 28 = 2x × 3x × 6x
22/7 × 49 × 28 = 36x3
x = (1078)1/3
TSA of cuboid = 2(lb+bh+hl) = 2(6x2+18x2+12x2) = 72x2 = 72(1078/9)2/3