InterviewSolution
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InterviewSolution
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Rahamal got a playing top (lattu) as his birthday presentation, which surprisingly had no colour on it. So he wanted to colour it with his crayons. The top is shaped like a cone surprisingly by a hemisphere. The entire top is5 cm in height and the diameter of the top is 3.5 cm. Find the area he has to colour. |
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Answer» Now, the curved surface area of the hemisphere `=1/2 xx 4 pi r^(2) = 2 pi r^(2) = (2xx(22)/(7)xx(3.5)/(2)xx(3.5)/(2))`sq-cm Also, the HEIGHT of the cone = height of the top - height ( radius) of the hemispherical part. `=(5-(3.5)/(2)) cm = 3.25`cm. So the slant height of the cone `=sqrt((3.5/2)^(2)+(3.25)^(2))cm=3.7cm` (APPROX) `:.` curved surface area of cone `=((22)/(7)xx(3.5)/(2)xx3.7)`sq-cm [ Formula `: pi r l` ] HENCE the total surface area of the top `=(2xx(22)/(7)xx(3.5)/(2)xx(3.5)/(2)) sq-cm + ((22)/(7)xx(3.5)/(2)xx3.7)sq-cm.=39.6 sq-cm `[(approx.)] |
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