If the ratio of volume to surface area of a sphere equals 7 cm. Find the total surface area of a sphere.

(Take )

Concept Used:

The volume of a Sphere

Surface Area of a Sphere = 4πr²,

Where r = radius of the sphere.

Given: The Ratio of Volume to the surface area of sphere = 7 cm

Assumption: Let r be the radius of the Sphere.

Explanation:

Ratio

⇒

⇒

⇒

⇒ r = 3 × 7 cm = 21 cm

Now, the total surface area of sphere = 4πr²

Putting the value of “r” we get,

T.S.A =

= 4 × 22 × 3cm × 21cm

= 5544 cm²

Hence, The Total Surface Area of Sphere = 5544 cm²