Question

The height of a right circular cylinder is 12m and also three times the sum of the areas of its two end faces is equal to twice the area of its curved surface. The radius of its base, in metre is? 

A 12 m Correct Answer Incorrect Answer
B 8 m Correct Answer Incorrect Answer
C 4 m Correct Answer Incorrect Answer
D 6 m Correct Answer Incorrect Answer

Solution

Height = 12cm,  Area of two end faces of right circular cylinder = (2πr2) Curved surface area of right circular cylinder = 2πrh according to question, 3 x (2πr2) = 2 x (2πrh) 3 x r = 2h r = (2×12)/3   r = 8 m

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