A cylinder has a curved surface area of 616 cm². Its height is 28 cm. What is the volume of the cylinder?

Height (h) of the cylinder = 28 cm

Let the radius of the cylinder be r.

Curved surface area of the cylinder = 2πrh = 616 cm²

$\Rightarrow 2\times \frac{22}{7}\times r\times 28=616$

$\Rightarrow r=\frac{616\times 7}{2\times 22\times 28}=\frac{7}{2} cm$

Volume of the cylinder

$={\mathrm{\pi r}}^2\mathrm{h}$

$=\frac{22}{7}\times {\left(\frac{7}{2}\right)}^2\times 28$

$=1078 {\mathrm{cm}}^3$

Therefore, the volume of the cylinder must be 1078 cm³.