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# The number of identical balls that can be made from a given amount of plastic is inversely proportional to the radius of each ball cubed.When the radius is 2mm,the number of balls is 350.Find the number of balls with a radius of 5mm,made of same amou?

assuming that the balls are spherical, we know the formula of a sphere to be: (4/3)(pi)(r^3) let’s say the number of balls produced from the the is “x”, then we know x is inversely proportional to (1/r^3) and therefore: x = k * (1/r^3) plugging in the numbers we have: 350 = k * (1/0.002^3) rearrange for k: k = 350 * (0.002^3) = 2.8*10^-6 now our formula is: x = 2.8*10^-6 * (1/r^3) we plug in 0.005 and we get: x = 2.8*10^-6 * (1/0.005^3)= 22.4 ~ 22 ·

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