Question : If the surface area of two spheres is in the ratio 81 : 25, then what is the ratio of their radius?
Option 1: 5 : 8
Option 2: 7 : 9
Option 3: 5 : 7
Option 4: 9 : 5
Correct Answer: 9 : 5
Solution :
Let the radii of two spheres be
According to the question,
Hence, the correct answer is 9 : 5.