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In Geometry, an object having width, height and depth is referred to as a 3D solid object. A sphere is a round solid object that is perfectly symmetrical and every point on its surface is equidistant from the center of the sphere.

A sphere does not have any vertices or edges like other solid objects. It has only one surface. There are many examples of spheres - ball, marbles etc.

The distance from the center of the sphere to any point on its surface is the radius of the sphere. The diameter of the sphere is the maximum distance between two points on the surface of the sphere.

Volume of a Sphere

The volume of a sphere is defined as the number of cubic units that will exactly fill the sphere.

If r is the radius of the of the sphere, then the volume of the sphere is given by the formula
Volume = 4/3  π r3

The volume is expressed in cubic units.

Practice questions:

Question: Find the volume of a sphere with radius equal to 3 cms.
π = 22 / 7
Volume of the sphere     = 4/3 * 22/ 7 * 3 * 3 * 3
= 113.14 cubic cms
)

Question: Find the volume of a sphere with radius equal to 1 cm.
π = 22 / 7
Volume of the sphere     = 4/3 * 22/ 7 * 1 * 1 * 1
= 4.19 cubic cms
)

Question: Find the volume of a sphere with diameter equal to 6 cm.
( Answer:    Diameter of the sphere = 6 cms
Radius of the sphere r = 6/2 = 3 cms
π = 22 / 7
Volume of the sphere     = 4/3 * 22/ 7 * 3 * 3 * 3
= 113.14 cubic cms
)

Area of the Sphere

If r is the radius of the sphere, the surface area of the sphere is given by the formula = 4 π r2

The area of the sphere is measured in sq cms.

Practice questions:

Question: Find the surface area of a sphere with radius equal to 7 cms.
Area of the sphere     = 4 * 22/7 * 7 * 7
= 616 sq cms
)

Question: Find the surface area of a sphere with diameter of 14 cms.
( Answer:     Diameter of the sphere = 14 cms
Radius of the sphere r = 14/2 = 7 cms
Area of the sphere     = 4 * 22/7 * 7 * 7
= 616 sq cms
)