If the radius and slant height of a cone are in the ratio 7 : 13 and its curved surface area is 286 cm2, find its radius.
We have
Let radius of cone = 7x
Let slant height = 13x
Curved surface area of cone = 286 cm2
= πrl = 286 , 22/7×7x×13x = 286
= x2 = 1
= x = 1
Hence radius of cone = 7×1 = 7 cm