Math's: Meaning of Surface Area and Volume: Surface Area, Volume of Sphere and Hemisphere

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The locus of a point which moves in space in such a way that its distance from a fixed point remains the same is called a sphere. The fixed point is called the center of the sphere and the same distance is called the radius () of the sphere. Examples of sphere are football, cricket ball, a marble etc.

Surface Area: Sphere

Surface Area: Sphere

Volume of Sphere-

Surface Area of Sphere-


If a sphere is cut into two equal parts by a plane passing through its center, then each part is called a hemisphere.

Surface Area: Hemisphere

Surface Area: Hemisphere

  • Volume of Hemisphere-

  • Curved Surface Area of Hemisphere-

  • Total Surface Area of Hemisphere-

1. Diameter of a hemispherical toy is . Find its

(i) curved surface area

(ii) total surface area

(iii) volume

Solution- Given, then,




2. A metallic solid ball of radius is melted and converted into small solid balls of radius each. Find the number of small balls so formed.


The number of small balls formed from the big ball is .

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