The radii of three concentric circles are in the ratio of 4 : 5 : 7. What is the ratio of the area between the two inner circles to that between the two outer circles?

Questions :

The radii of three concentric circles are in the ratio of 4 : 5 : 7. What is the ratio of the area between the two inner circles to that between the two outer circles ?

Options :

• 4 : 7
• 5 : 9
• 4 : 5
• 3 : 8

correct answer : d)