Question

find the total surface area of hollow cylinders of 27 cm high, whose external diameter is 44 cm and thickness is 7cm. ​

Answer 1

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Hey Mate!!

• Given,

Height = 27 cm

External Diameter = 44 cm

=> External Radius = 22 cm

=> Internal Radius = 22 - 7 = 15 cm

• CSA of Cylinder = 2πrh

=> Internal CSA:

$= > 2 \times \frac{22}{7} \times15 \times 27 \\ = > 2545.72 \: {cm}^{2}$

External CSA:

$= > 2 \times \frac{22}{7} \times 22 \times 27 \\ = > 3733.72 \: {cm}^{2}$

Area of top and base = 2 × Area of circle

=> 2 × πr^2

$= > 2 \times \frac{22}{7} \times 22 \times 22 \\ = > 3042.29 \: {cm}^{2}$

Thus, total surface area:

$2545.72 +3733.72 + 3042.29 \\ = > 9321.73 \: {cm}^{2}$

Hope it helps...✌️✌️