I was on Yahoo! Answers and I asked: "Flat-earthers: If the earth was really flat or cubical or rectangularly prismatic, how could the moon rotate around it?", and I was told, "The diameter of the earth is about 1/30 of the moon's distance from it. So if the earth were a cube of that size, it would make very little difference to the moon's orbit. That's how a flat-earther who knows his Newtonian physics would answer."
I responded with "The diameter of the earth is about 7,917.5 mi. so when you say "if the earth were a cube of that size", do you mean a cube with the length of one side being 7,917.5 mi.? A 7,917.5 mi. * 7,917.5 mi. * 7,917.5 mi. cube, or a cube with a volume of (7,917.5)^3 mi.^3?"
Am I right or am I missing something? What does "if the earth were a cube of that size" mean?
Someone there responded with, "As a simple geometry question? The volume of a sphere is V = (4/3) pi r^3. The volume of a cube is V = R^3. The volume of the (spherical) Earth is 2.59876×10^11 cubic miles. So a cube with the same volume would have sides of length 6381.49 miles. 6381.49^3 = 2.59876×10^11 The moon's average distance is nearly 29.01 times the Earth's average diameter."
Okay, but IS this a volume question? How do we know this is a about volume and not surface area?
Please help- thank you.