## 29- If the volume and surface area of a sphere are numerically equal then its radius is-.(a) 2 units (b) 3 units (c) 4 units (d

Question

29- If the volume and surface area of a
sphere are numerically equal then its radius
is…..(a) 2 units (b) 3 units (c) 4 units (d) 5
units​

in progress 0
1 month 2021-10-26T11:17:32+00:00 2 Answers 0 views 0

Step-by-step explanation:

• Volume of a sphere = Surface area of sphere

• The radius of the sphere

→ First we have to find the volume of the sphere.

→ Volume of a sphere is given by

Volume of a sphere = 4/3 × π × r³—–(1)

→ Now we have to find the surface area of the sphere

→ Surface area of a sphere is given by

Surface area of a sphere = 4 π r²——(2)

→ By given we know that

LHS of equation 1 and 2 are equal, hence RHS must also be equal.

4/3 π r³ = 4 π r²

→ Cancelling 4 , π and r² on both sides

1/3 r = 1

r = 1 × 3

r = 3 units

→ Hence the radius of the sphere is 3 units

→ Hence option b is correct

→Volume of a sphere = 4/3 × π × r³

→  Surface area of a sphere = 4 π r²

## 3

Step-by-step explanation: