English
Maharashtra State BoardSSC (English Medium) 9th Standard

If the radius of a solid hemisphere is 5 cm, then find its curved surface area and total surface area. ( π = 3.14 ) - Geometry

Advertisements
Advertisements

Question

If the radius of a solid hemisphere is 5 cm, then find its curved surface area and total surface area. ( π = 3.14 )

Sum
Advertisements

Solution

Radius of the hemisphere, r = 5 cm

∴ Curved surface area of the hemisphere = 2πr

= 2 × 3.14 × (5)2 

= 157 cm2

Total surface area of the hemisphere = 3πr

= 3 × 3.14 × (5)2 

= 235.5 cm2

Thus, the curved surface area and total surface area of the solid hemisphere is 157 cm2 and 235.5 cm2, respectively.

shaalaa.com
  Is there an error in this question or solution?
Chapter 9: Surface Area and Volume - Practice Set 9.3 [Page 123]

APPEARS IN

Balbharati Mathematics 2 [English] Standard 9 Maharashtra State Board
Chapter 9 Surface Area and Volume
Practice Set 9.3 | Q 2. | Page 123

RELATED QUESTIONS

Find the surface area of a sphere of diameter 14 cm.

`["Assume "pi=22/7]`


Find the surface area of a sphere of diameter 21 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 right circular cylinder just encloses a sphere of radius r (see figure). Find

  1. surface area of the sphere,
  2. curved surface area of the cylinder,
  3. ratio of the areas obtained in (i) and (ii).


A certain number of metallic cones, each of radius 2 cm and height 3 cm are melted and recast into a solid sphere of radius 6 cm. Find the number of cones.


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.


The surface area of a solid metallic sphere is 2464 cm2. It is melted and recast into solid right circular cones of radius 3.5 cm and height 7 cm. Calculate:

  1. the radius of the sphere.
  2. the number of cones recast. (Take π = `22/7`)

Find the surface area of a sphere of diameter 21 cm.


A hemispherical bowl made of brass has inner diameter 10.5 cm. Find the cost of tin- plating
it on the inside at the rate of Rs. 4 per 100 `cm^2`


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 surface area of a sphere is 2464 cm2, find its volume. 


A spherical ball of lead has been melted and made into identical smaller balls with radius equal to half the radius of the original one. How many such balls can be made?


Eight metallic spheres; each of radius 2 mm, are melted and cast into a single sphere. Calculate the radius of the new sphere. 


The surface area of a solid sphere is increased by 12% without changing its shape. Find the percentage increase in its:

  1. radius
  2. volume

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. 


Find the maximum volume of a cone that can be carved out of a solid hemisphere of radius r cm. 


A largest sphere is to be carved out of a right circular cylinder of radius 7 cm and height 14 cm. Find the volume of the sphere. 


If a hollow sphere of internal and external diameters 4 cm and 8 cm respectively melted into a cone of base diameter 8 cm, then find the height of the cone.


The ratio of the total surface area of a sphere and a hemisphere of same radius is


A sphere and a cube are of the same height. The ratio of their volumes is 


The largest sphere is cut off from a cube of side 6 cm. The volume of the sphere will be


A cylindrical rod whose height is 8 times of its radius is melted and recast into spherical balls of same radius. The number of balls will be


If a solid sphere of radius r is melted and cast into the shape of a solid cone of height r, then the radius of the base of the cone is


A sphere is placed inside a right circular cylinder so as to touch the top, base and lateral surface of the cylinder. If the radius of the sphere is r, then the volume of the cylinder is 


The ratio between the volume of a sphere and volume of a circumscribing right circular cylinder is 


A cone, a hemisphere and a cylinder stand on equal bases and have the same height. The ratio of their volumes is


The internal and external diameters of a hollow hemi-spherical vessel are 21 cm and 28 cm respectively. Find volume of material of the vessel.


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 surface area of a solid metallic sphere is 2464 cm2. It is melted and recast into solid right circular cones of radius 3.5 cm and height 7 cm. Calculate : the number of cones recast.  `("Take"  pi =22/7)`


A conical tent is to accommodate 77 persons. Each person must have 16 m3 of air to breathe. Given the radius of the tent as 7 m, find the height of the tent and also its curved surface area. 


The volume of a sphere is 905 1/7 cm3, find its diameter.


A sphere cut out from a side of 7 cm cubes. Find the volume of this sphere?


The radius of a sphere is 10 cm. If we increase the radius 5% then how many % will increase in volume?


The cylinder of radius 12 cm have filled the 20 cm with water. One piece of iron drop in the stands of water goes up 6.75 cm. Find the radius of sphere piece.


A spherical ball of radius 3 cm is melted and recast into three spherical balls. The radii of two of the balls are 1.5 cm and 2 cm. Find the diameter of the third ball.


The total surface area of a hemisphere is how many times the square of its radius


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×