English

Find the surface area of a sphere of diameter 3.5 cm . - Mathematics

Advertisements
Advertisements

Question

Find the surface area of a sphere of diameter 3.5 cm.

Sum
Advertisements

Solution

Diameter = 3.5cm

Radius = `(3. 5cm)/2 -1.75 cm.`

∴ Surface area = `4πr^2 - 4 × 22/7 × (3.5)/(2^2)`

= 38.5 cm 2

shaalaa.com
  Is there an error in this question or solution?
Chapter 21: Surface Areas and Volume of a Sphere - Exercise 21.1 [Page 8]

APPEARS IN

RD Sharma Mathematics [English] Class 9
Chapter 21 Surface Areas and Volume of a Sphere
Exercise 21.1 | Q 2.3 | Page 8
Nootan Mathematics [English] Class 10 ICSE
Chapter 17 Mensuration
Exercise 17C | Q 2. (iii) | Page 390

RELATED QUESTIONS

Find the surface area of a sphere of radius 5.6 cm.

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


Find the surface area of a sphere of diameter 3.5 m.

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


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]`


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?


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


The volume of a sphere is 38808 cm3; find its diameter and the surface area.


The volume of one sphere is 27 times that of another sphere. Calculate the ratio of their :

  1. radii,
  2. surface areas. 

Metallic spheres of radii 6 cm, 8 cm and 10 cm respectively are melted and recasted into a single solid sphere. Taking π = 3.1, find the surface area of the solid sphere formed.


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

Total volume of three identical cones is the same as that of a bigger cone whose height is 9 cm and diameter 40 cm. Find the radius of the base of each smaller cone, if height of each is 108 cm. 


A hollow sphere of internal and external radii 6 cm and 8 cm respectively is melted and recast into small cones of base radius 2 cm and height 8 cm. Find the number of cones.


The diameter of a sphere is 6 cm. It is melted and drawn into a wire of diameter 0.2 cm. Find the length of the wire. 


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:

  1. its volume,
  2. the surface area of the tunnel (excluding the floor) and
  3. its floor area.   


Find the radius of a sphere whose surface area is 154 cm2.

 

Find the volume of a sphere whose surface area is 154 cm2.

 

How many spherical bullets can be made out of a solid cube of lead whose edge measures 44 cm, each bullet being 4 cm in diameter?


If a sphere of radius 2r has the same volume as that of a cone with circular base of radius r, then find the height of the cone.


The surface area of a sphere of radius 5 cm is five times the area of the curved surface of a cone of radius 4 cm. Find the height of the cone.

 

If a sphere is inscribed in a cube, then the ratio of the volume of the sphere to the volume of the cube is


Find the surface area of a sphere, if its volume is 38808 cubic cm. `(π = 22/7)`


Find the length of the wire of diameter 4 m that can be drawn from a solid sphere of radius 9 m. 


A solid metallic cylinder has a radius of 2 cm and is 45 cm tall. Find the number of metallic spheres of diameter 6 cm that can be made by recasting this cylinder . 


There is a ratio 1: 4 between the surface area of two spheres, find the ratio between their radius.


The radius of two spheres are in the ratio of 1 : 3. Find the ratio between their volume.


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


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 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


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×