A cylinder of total surface area is 3140cm. The cylinder is melted down to make solid cubes of length 2cm. Taking pi=3.14, calculate that number of cubes that are made.

1 answer

2πr(r+h) = 3140
Unfortunately, the cylinder could be very tall and thin, with almost zero volume, or very wide and flat, again with almost zero volume.
Note that 3140 = 1000π
So, r(r+h) = 500
So let's take r=20, h=5
That gives a volume of 2000π = 6280
so it will take 6280/2^3 = ___ cubes.

You can, of course, use other values for r and h.