CBSE Class 9 - Surface Area: Sphere and Hemisphere Videos

• find the radius of a sphere whose area is 154 cm
• Can you please answer these all questions
  
• If a sphere and a hemisphere have the same surface area, find the ratio of their radii if r1 is the radius of the sphere and r2 is the radius of the hemisphere. 
• The diameter of the moon is approximately one fourth of the diameter of the earth. Find the ratio of their surface areas
• If the area of the top of a hemispherical bowl is 154 cm2. Its volume is 714.65 cm3(app.)  718.67 cm3 (app.) 716.92 cm3 (app.) 720.46 cm3 (app.)
• A hemispherical bowl is made of steel, 0.7 cm thick has inner radius 14 cm. It is to be polished from inside and outside. Calculate the total area to be polished.
• Two hemispherical bowls are formed by cutting a spherical ball of diameter 28 cm from the centre. Calculate the total surface area of each of the hemispherical bowls so formed.
• A toy is in the form of a hemisphere surmounted by a cone of radius 3 cm and height 4 cm. Calculate the surface area of the toy.
• If the circumference of the base, a hemispherical dome of a building is 352 cm, find the lateral surface area of the dome.
• The hollow sphere, in which the circus motorcyclist performs his stunts, has a radius of 2.8 m. find the area available to the motorcyclist for riding.

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