The curved surface area and the volume of a cylinder are 1320 cm2 and 9240 cm3 respectively. What is the height of the cylinder? (Take \(\pi=\frac{22}{7}\))
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 15 cm
Dividing the volume \(\pi r^2h\) by the curved surface area \(2\pi rh\) leaves \(\frac{r}{2}\), which gives the radius at once; then the curved surface area gives the height.
\(\displaystyle\frac{\pi r^2h}{2\pi rh}=\frac{r}{2}=\frac{9240}{1320}=7\), so \(r=14\) cm
\(\displaystyle2\times\frac{22}{7}\times14\times h=1320\), so \(88h=1320\)
\(h=15\) cm
