The total surface area of a solid cube is 4.86 m2 . It is melted and recast into a right circular cylinder of radius 0.3 m. What is the height (in m)of the cylinder (correct to one decimal place)? Take $ \pi = \frac{22}{7}$.
Answer & explanation
Correct answer: option 2
We know that,
If a is the side then,
Total surface area of cube = 6a2
Volume of cube = a3
Volume of cylinder = Π r2h
We have,
Total surface area of a solid cube = 4.86 m2
Radius of cylinder = 0.3 m.
According to formula,
6a2 = 4.86
= a2 = 0.81
= a = 0.9 m
ATQ, Volume of cube = volume of cylinder
= (0.9)3 = \(\frac{22}{7}\) × (0.3)2 × h
= h = 2.6 m.