2021 · Q33
The ratio of the radius of base to the height of a cylinder is 2 ∶ 3. If the volume of the cylinder is 1617 cm³, then what is the curved surface area of the cylinder? (Take π = 22/7)
Elementary MathematicsMensuration
- A242 cm²
- B385 cm²
- C462 cm²
- D770 cm²
Explanation
Write r = 2k, h = 3k. Volume πr²h = 12πk³ = 1617, so k³ = 1617·7/(12·22) = 343/8 and k = 7/2. Thus r = 7, h = 10.5, and the curved surface area 2πrh = 2·(22/7)·7·10.5 = 462 cm². Hence option C.