What is the height of a solid right circular cylinder whose radius is 3 cm and total surface area is 60π cm2?
Explanation:
Total surface area of a cylinder = 2πrh + 2πr2 = 60π
⇒ 2rh + 2r2 = 60
⇒ 2 × 3 × h + 2 × 32 = 60
⇒ 2 × 3 × h + 18 = 60
⇒ 6 × h = 42
⇒ h = 7
Hence, option (c).