The curved surface area and volume of a cylinder are 660 cm² and 1650 cm³, respectively. What is the height of this cylinder? 

21 cm

Curved surface area of cylinder ⇒ 2\(\pi \)rh = 660 cm²

Volume = \(\pi \)r²h = 1650 cm²

                       \(\frac{volume}{l.s.a.}\) = \(\frac{\Pi r^2h }{2\Pi rh}\)

⇒ Therefore, \(\frac{1650}{660}\) = \(\frac{r}{2}\)

⇒ r = 5

C.S.A. = 660

⇒ 2\(\pi \)rh = 660

⇒ 2 × \(\frac{22}{7}\) × h × 5 = 660

⇒ h =  \(\frac{660 × 7}{2 × 22 × 5}\) = 21 cm