Question

the radius and height of a cylinder are in the ratio 7 is to 2 if the volume of cylinder is 8316 cm cube find the total surface area of cylinder

Answer 1

Sol: Let ratio of radius and height of a cylinder are 7x : 2x. Volume of the cylinder (V) = πr2h 8316 = (22/7)(7x)2(2x) ⇒ 8316 = (22 x 14) x3 ⇒ x3 = 8316 / 308 ⇒x3 = 27
∴x = 3.
 radius of the cylinder = 7 x3 = 21 cm. 
height of the cylinder = 2x 3 = 6 cm

Total surface area of the cylinder = 2πr( r + h) = 2 x (22/7) 21( 21 + 6) = 2 x 22 x 3 x 27 = 3564 cm2 

Answer 2

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