Questions :
The ratio of the circumferences of two circular flower beds is 4:5. If the smaller flower bed has a radius of 12 m, what is the radius of the larger flower bed ?
Options :
- 15 m
- 17 m
- 19 m
- 21 m
correct answer : a)
Explanation :
The circumference of a circle is given by the formula C = 2πr. Since the circumference is directly proportional to the radius, the ratio of the radii will be the same as the ratio of the circumferences. Given that the ratio of circumferences is 4 : 5 and the radius of the smaller flower bed is 12 m, we have 12 / r = 4 / 5. Solving this gives 4r = 60, therefore r = 15 m. Hence, the radius of the larger flower bed is 15 m. Option (b) 17 m, option (c) 19 m, and option (d) 21 m do not satisfy the given ratio and are therefore incorrect.