Q9 of 67 Page 190

The height and radius of a cylinder are 7.5 cm and 3.5 cm respectively. Find the ratio between the total surface area and curved surface area of the cylinder

Let r be the radius and h be the height of cylinder


h = 7.5 cm = cm


r = 3.5 cm = cm


total surface area = 2πrh + 2πr2


curved surface area = 2πrh


ratio of total surface area to curved surface area =


⇒ ratio =


⇒ ratio =


⇒ ratio = 1 +


⇒ ratio = 1 +


⇒ ratio = 1 +


⇒ ratio =


⇒ ratio =


Therefore, ratio between the total surface area and curved surface area of the cylinder is 22:15


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