The surface area of two spherical balls is in the ratio 4:9. Find the radius of the bigger ball, if the radius of the smaller ball is 4cm.

Q. The surface area of two spherical balls is in the ratio 4:9. Find the radius of the bigger ball, if the radius of the smaller ball is 4cm:

A) 5cm

B) 7.5cm

C) 6cm

D) 9cm

Solution: In this ques we have given that the surface area of two spherical balls is in the ratio of 4:9

Let us consider that radius of smaller ball is denoted by 'r' and radius of bigger ball is denoted by 'R'

Also radius of smaller ball is 4 cm i.e., r = 4 cm

As we know very well that surface area of sphere is 4πr²

Therefore, according to the ques

4πr²/4πR² = 4/9

r²/R² = 4/9

Since r = 4 given in the ques

4²/R² = 4/9

Simplifying

R² = (9 × 4²)/4

R = ²√36

R = 6 cm

Thus Option (C) the radius of bigger spherical ball is 6 cm.