Q157
ArithmeticGeometry & Mensuration
The ratio of the radius of two circles is 5 : 4. What is the ratio of their areas?
- a.5 : 4
- b.25 : 16
- c.6 : 7
- d.9 : 13
Answer: (B) 25 : 16
Area = $\pi r^2$. Ratio of areas = $\frac{\pi(5r)^2}{\pi(4r)^2} = \frac{25}{16}$. So the ratio is 25 : 16.