Question

Curved surface area of a cylinder is 1980 cm² and radius of its base is 15 cm. Find the height of the cylinder. (π = ${\displaystyle \frac{22}{7}}$)

Answer 1

Let the height of the cylinder be h cm.

Radius of the cylinder, r = 15 cm

Curved surface area of the cylinder = 1980 cm²
∴ 2πrh = 1980 cm²

⇒ ${\displaystyle 2\times \frac{22}{7}\times 15\times \text{h}=1980}$

⇒ ${\displaystyle \text{h}=\frac{1980\times 7}{2\times 22\times 15}}$

⇒ ${\displaystyle \text{h}=\frac{{\cancel{1980}}^3\times 7}{{\cancel{660}}_1}}$

⇒ h = 3 × 7

⇒ h = 21 cm

Thus, the height of the cylinder is 21 cm.