The curved surface area of one cone is twice that of the other while the slant height of the latter is twice that of the former. The ratio of their radii is

Curved surface area of a cone =


Given that curved surface area of 1st = 2× curved surface area of 2nd


And slant height of 2nd = 2× slant height of 1st


⇒ L= 2l




⇒ r : R = 4 : 1

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