1. Curved surface area of a cone is thrice and curved surface area of the other. Slant height of
second cone is thrice the slant height of first. Find ratio of their radii.
Curved Surface Area of a cone=∏rl
let 
for first cone
and
for second cone.
CSA of first cone=3( CSA of second cone)
Thus, the ratio of their radii = 9:1