Question

The diameter of the base of a right circular cylinder is 42 cm and its height is 10 cm. Find the area of the curved surface and total surface area.
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Answer 1

Answer:

Curved surface area of cylinder

= 1320 sq.cm

total surface area of cylinder

= 4092 sq.cm

Step-by-step explanation:

We have,

Diameter of the base of the cylinder = 42 cm

∴ r = Radius of the base of the cylinder = 21 cm

h = Height of the cylinder = 10 cm

∴ Curved surface area of the cylinder = 2πrh

$= 2 \times \frac{22}{7} \times 21 \times 10 \: cm^{2} \\ \\ = 2 \times 22 \times 3 \times 10 \: cm ^{2} = 1320 \: cm ^{2}$

Total surface area of the cylinder

= 2πr( h+r)

$= 2 \times \frac{22}{7} \times 21 \times (10 + 21) \: cm ^{2} \\ \\ = 2 \times 22 \times 3 \times 31 \: cm^{2} = 4092 \: cm ^{2}$