Question

Two cones are similar in shape and the ratio of corresponding lengths is 3:5. (a) if the radius of the smaller cone is 12cm, find the radius of the larger cone. (b) if there is sufficient paint to paint 216 larger cones, find how many of the smaller cones can be painted with the same amount of paint. (c) If the same amount of paint covers 24 similar cones, find the radius of one of these cones. Need help with part c .Thanks

Answer 1

I assume you got
(a) r = 20
(b) n = 600
(c) total volume of paint for 216 large cones is 216 * 400π/3
divide that by 24 and you get 3600 π/3 = π/3 * 60^2
so, r=60

Yeah, I know there's a factor of h involved in the area, but it is everywhere, and cancels out. So I just assumed h=1 to make things simpler.

Answer 2

thx dude