Advertisements
Advertisements
Question
A bus stop is barricated from the remaining part of the road, by using 50 hollow cones made of recycled card-board. Each cone has a base diameter of 40 cm and height 1 m. If the outer side of each of the cones is to be painted and the cost of painting is Rs. 12 per m2, what will be the cost of painting all these cones. (Use 𝜋 = 3.14 and √1.04 = 1.02)
Solution
Radius of cone`(r)=40/2=20m=0.2m`
Height of cone=1m
Slant height of cone(l)`=sqrt(h^2+r^2)`
=`sqrt(1^2+(0.2)^2m)`
=`sqrt(1.04m=1.02m)`
Curved surface area of each one
=`pirl=(3.14xx0.2xx1.02)m^2`
=` 0.64056m^2`
CSA of 50 such cone`=50xx0.64056m^2=32.028m^2`
Cost of painting` 1m^2` area=Rs.12.
Cost of painting` 32.028m^2 area=Rs(32.028xx12)`
= Rs.384.326PS
Thus, it will cost Rs. 38434 (Approx) in painting the so hollow cones.
APPEARS IN
RELATED QUESTIONS
A hemispherical bowl of diameter 7.2 cm is filled completely with chocolate sauce. This sauce is poured into an inverted cone of radius 4.8 cm. Find the height of the cone.
Find the curved surface area of a cone, if its slant height is 60 cm and the radius of its base is 21 cm.
Find the curved surface area of a cone with base radius 5.25 cm and slant height 10cm.
A cylinder and a cone have equal radii of their bases and equal heights. If their curved surface areas are in the ratio 8:5, show that the radius of each is to the height of each as 3:4.
Monica has a piece of Canvas whose area is 551 m2. She uses it to have a conical tent made, with a base radius of 7m. Assuming that all the stitching margins and wastage incurred while cutting, amounts to approximately 1 m2. Find the volume of the tent that can be made with it.
A hemispherical bowl of diameter 7.2 cm is filled completely with chocolate sauce. This sauce is poured into an inverted cone of radius 4.8 cm. Find the height of the cone if it is completely filled.
The given figure shows the cross section of a water channel consisting of a rectangle and a semi-circle. Assuming that the channel is always full, find the volume of water discharged through it in one minute if water is flowing at the rate of 20 cm per second. Give your answer in cubic metres correct to one place of decimal.
A solid, consisting of a right circular cone standing one a hemisphere, is placed upright in a right circular cylinder, full of water, and touches the bottom. Find the volume of water left in the cylinder, having given that the radius of the cylinder is 3 cm and its height is 6 cm; the radius of
the hemisphere is 2 cm and the height of cone is 4 cm. Give your answer to the nearest cubic centimeter.
A buoy is made in the form of a hemisphere surmounted by a right circular cone whose circular base coincides with the plane surface of the hemisphere. The radius of the base of the cone is 3.5 m and its volume is two-third the volume of hemisphere. Calculate the height of the cone and the surface area of the buoy, correct to two decimal places.
A cone and a hemisphere have equal bases and equal volumes. Find the ratio of their heights.
