Question

Find the curved surface area of a cylinder of height 21 cm and base radius 5 cm

Answer 1

csa = 2πrh
= 2 * 22/7 * 5 * 21
= 44 * 15
= 660

Answer 2

Hey mate..
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Given,

Height of the cylinder , h = 21cm

Base radius of the cylinder, r = 5cm

Curved Surface area of the cylinder = ?

We know,

Curved Surface area of the cylinder = $2\pi \: rh \\ = 2 \times \frac{22}{7} \times 5 \times 21 \\ \\ = 660 \: cm {}^{2}$

Hope it helps !!!