A tent is of the shape of a right circular cylinder upt a height of 3 metres and then becomes a right circular cone with a maximum height of 13.5 metres above the ground. Calculate the cost of paintingthe inner side of the tent at the rate of Rs. 2 per square metre, if the radius of the base is 14 metres.

Explanation

Given:
Radius of base of cylindrical portion`=14m`
Height of cylindrical portion`=3m`
Curved surface area of cylindrical part`=2xx22/7xx14xx3`
Height of conical part`=13.5−3=10.5m`
For conical part:
`r=14m`, `h=10.5m`
`l=sqrt((14)^2+(10.5)^2)=sqrt(306.25)`
`l=17.5m`
`CSA` of conical part`=πrl=22/7xx14xx17.5=770m^3`
`:.`Total area to be painted`=(264+770)m^2=1034m^2`
Cost of painting`=Rs.(1034xx2)=Rs.2068`
Hence, the cost of paining the inner side of paint is `Rs.2068`.