15 identical solid metallic spheres of radius 3 cm are melted to form a single solid sphere. 259.97 cm³ of the material was lost in the process. What is the surface area of the newly formed sphere?
Answer & explanation
Correct answer: option 4
Volume of 15 smaller spheres = 15 \(\frac{4}{3}\) \(\pi \) (3)³ = 1695.6 cm³
Given, 259.97 cm³ was lost
Thus Volume of new sphere = 1435.63cm³ = \(\frac{4}{3}\) \(\pi \) (r)³
r = 7 cm
Surface area = 4 \(\pi \) r² = 616 cm²