Practicing Success
A solid metallic cylinder of base radius 4 cm and height $5\frac{1}{3}$ cm is melted and recast into a sphere. What is the surface area of the sphere, in cm2? |
64 π 96 π 80 π 40 π |
64 π |
We know that, Volume of sphere = \(\frac{4}{3}\)πR3 Surface area of sphere = 4 πR2 Volume of cylinder = πr2h Radius of cylinder r = 4 cm We have, Height of cylinder h = \(\frac{16}{3}\) cm Now, \(\frac{4}{3}\) × πR3 = πr2h R3 = 4 × 4 × \(\frac{16}{3}\) × \(\frac{3}{4}\) R = 4 cm Surface area of sphere = 4π × 42 = 64π cm2 |