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mathematicsprinted 100 · PDF 101
165 pagesrevision 46935
printed 100 · PDF 101
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c) - The cube’s volume would be 203, which would be 8000
cm3. Dividing this by 40 spheres which would use this total
volume, we get the volume of one sphere as 200 cm3. Substituting this value
of V into the volume formula, we can find r to be 3.63 cm approximately.
d) - Since the surface areas are equal, we would set the surface area of the
cylinder as equal to that of the sphere. So 2*pi*x2+2*pi*x2*7/2 = 4*pi*R2.
Simplifying the left hand side, we get 9*pi*x2 = 4*pi*R2. Dividing both sides by
4*pi, we get R2 = 9x2/4. Taking the square root of both sides, we can get R in
terms of x. This gives R = 3x/2.