# Determine a volume and the diameter of a 12.5kg gold sphere?

GROUPS:
 A standard gold bar weighs 12.5kg. The density of gold is 19.3g/cm^3. What is the diameter of a sphere made from the same gold bar? I have tried various versions of the question in WolframAlpha. WA will happily understand and return the diameter of a sphere of a certain volume. Is there a way to get it to return the answer in one question?
Answer
1 year ago
4 Replies
 first calculate the volume from the mass and the density, then calculate the diameter of the sphere from the volume.
Answer
1 year ago
 Yes that would work. I have no issue with doing this on paper even by hand without a calculator! If I type in Wolfram Alpha "diameter of sphere of volume 10" it will not only understand the question and interpret it but also return the answer. If I type "Volume of a sphere of volume of a gold bar" it fails. As does "Volume of a sphere of volume of a solid of 12.5 kg and a density of 19.3g/cm^3"Can I get it to solve the problem in one pass?
Answer
1 year ago
 Perhaps solve 4/3 pi r^3=12.5 kg/19.3 g/cm^3 for r WolframAlpha linkI tried to get it to understand something like weight=12.5 kg, density=19.3g/cm^3, volume=weight/density, solve 3/4 pi r^3=volume for r but had no success
Answer
1 year ago
 Solve[(4 Pi/3)* r^3 == m*d, r]
Answer
1 year ago