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प्रश्न
The slant height and base diameter of a conical tomb are 25 m and 14 m respectively. Find the cost of white-washing its curved surface at the rate of ₹ 210 per 100 m2.
`["Assume "pi=22/7]`
उत्तर
Slant height (l) of conical tomb = 25 m
Base radius (r) of tomb = `14/2` = 7 m
Curved surface area of conical tomb = πrl
=`(22/7 xx 7 xx 25) m^2`
= 550 m2
Cost of white-washing 100 m2 area = ₹ 210
Cost of white-washing 550 m2 area = `₹((210xx550)/100)`
= ₹ 1155
Therefore, it will cost ₹ 1155 while white-washing such a conical tomb.
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