The radii of the bases of two right circular cylinders are in the ratio of 3 : 4 and their heights are in the ratio of 4 : 5, The ratio of their curved surface areas is
1
4 : 9
2
3 : 5
3
5 : 12
4
7 : 12
The radii of the bases of two right circular cylinders are in the ratio of 3 : 4 and their heights are in the ratio of 4 : 5, The ratio of their curved surface areas is