Advertisements
Advertisements
प्रश्न
The internal and external diameters of a hollow hemispherical vessel are 20 cm and 28 cm respectively. Find the cost to paint the vessel all over at ₹ 0.14 per cm2
Advertisements
उत्तर
Internal radius (r) = `20/2` = 10 cm
External radius (R) = `28/2` = 14 cm
T.S.A of a hollow hemisphere
= π (3R2 + r2) sq.units
= `22/7[3 xx 14^2 + 10^2]` cm2
= `22/7[588 + 100]` cm2
= `22/7 xx 688` cm2
Cost of painting the vessel
= `₹ 0.14 xx 22/7 xx 688`
= `₹ 14/100 xx 22/7 xx 688`
= `₹ (2 xx 22 xx 688)/100`
= `₹ 30272/100`
= ₹ 302.72
Cost of painting = ₹ 302.72
APPEARS IN
संबंधित प्रश्न
Find the surface area of a sphere of radius 5.6 cm.
`["Assume "pi=22/7]`
The radius of a spherical balloon increases from 7 cm to 14 cm as air is being pumped into it. Find the ratio of surface areas of the balloon in the two cases.
A hemispherical bowl is made of steel, 0.25 cm thick. The inner radius of the bowl is 5 cm. Find the outer curved surface area of the bowl.
`["Assume "pi = 22/7]`
A model of a ship is made to a scale 1: 300
1) The length of the model of the ship is 2 m. Calculate the lengths of the ship.
2) The area of the deck ship is 180,000 m2. Calculate the area of the deck of the model.
3) The volume of the model in 6.5 m3. Calculate the volume of the ship.
A solid cone of radius 5 cm and height 8 cm is melted and made into small spheres of radius 0.5 cm. Find the number of spheres formed.
Find the surface area of a sphere of radius 10.5 cm.
Find the surface area of a sphere of radius 5.6 cm.
Find the total surface area of a hemisphere and a solid hemisphere each of radius 10 cm.
(Use 𝜋 = 3.14)
The surface area of a sphere is 5544 `cm^2`, find its diameter.
Assuming the earth to be a sphere of radius 6370 km, how many square kilo metres is area
of the land, if three-fourth of the earth’s surface is covered by water?
A cylinder of same height and radius is placed on the top of a hemisphere. Find the curved
surface area of the shape if the length of the shape be 7 cm.
The volume of one sphere is 27 times that of another sphere. Calculate the ratio of their :
- radii,
- surface areas.
A solid sphere of radius 15 cm is melted and recast into solid right circular cones of radius 2.5 cm and height 8 cm. Calculate the number of cones recast.
A solid rectangular block of metal 49 cm by 44 cm by 18 cm is melted and formed into a solid sphere. Calculate the radius of the sphere.
The cross-section of a tunnel is a square of side 7 m surmounted by a semi-circle as shown in the adjoining figure. The tunnel is 80 m long.
Calculate:
- its volume,
- the surface area of the tunnel (excluding the floor) and
- its floor area.
If the ratio of volumes of two spheres is 1 : 8, then the ratio of their surface areas is
If the radius of a solid hemisphere is 5 cm, then find its curved surface area and total surface area. ( π = 3.14 )
If the surface area of a sphere is 2826 cm2 then find its volume. ( π= 3.14)
A hemispherical bowl of internal radius 9 cm is full of liquid. This liquid is to be filled into conical shaped small containers each of diameter 3 cm and height 4 cm. How many containers are necessary to empty the bowl?
The radius of two spheres are in the ratio of 1 : 3. Find the ratio between their volume.
