SOLUTION: Two metallic solid right circular cones have same height h.The radii of their base are r1 and r2. The two cones are melted together and recast into a solid right circular cylinder

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Question 727392: Two metallic solid right circular cones have same height h.The radii of their base are r1 and r2. The two cones are melted together and recast into a solid right circular cylinder of height h.Show that the radius of the base of the cylinder is sqrt (1 upon 3 r1^2 + r2^2 )
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
1/3pih(r1^2+r2^2) Volume of both cones
which = pir^2h volume of cylinder

pir%5E2h+=pi%2A+1%2F3%2Ah%28r1%5E2%2Br2%5E2%29

r%5E2=1%2F3%28r1%5E2%2Br2%5E2%29
r=+sqrt%281%2F%283%28r1%5E2%2Br2%5E2%29%29%29