There are two cones. The curved surface area of one is twice that of the other. The slant height of the later is twice that of the former. Find the ratio of their radii.

Explanation

Curved Surface Area of 1st cone`=`Curved Surface Area of 2nd cone
`=>pir_1l_1=pir_2l_2`
`:.l_2=2l_1`
`=>pir_1l_1=2xxpir_2xx2l_1`
`=>r_1/r_2=(4pirl_1)/(pirl_1)=4/1`
`=>r_1:r_2=4:1`
`therefore` The ratio of their radii`=4:1`