Q) In the diagram given below, a tilted right circular cylindrical vessel with base diameter 7 cm contains a liquid. When placed vertically, the height of the liquid in the vessel is the mean of two heights shown in the diagram. Find the area of wet surface, when the cylinder is placed vertically on a horizontal surface. (Use π= 22/7 )

ICSE Specimen Question Paper (SQP) 2026

Ans:

Step 1: Let’s imagine that the cylinder is not tilted and kept vertically – make a new diagram for our better understanding of the question:

Step 2: Here, new height, h is mean of 2 heights shhown.

hence, h = = 3.5 cm

also given that diameter of the cylinder, d = 7 cm

hence, radius r = = 3.5 cm

Step 3: Wet surface Area = Curved surface area till height h + base area

= 2  π r h + π r 2 = π r (2 h + r)

By substituting values of π, h & r, we get:

Wet surface area = (3.5) (2 x 3.5 + 3.5)

=  x 3.5 x 10.5 = 22 x 0.5 x 10.5

= 11 x 10.5 = 115.5 cm²

Therefore, the wet surface area of the cylinder is 115.5 cm².

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