The ancient Great Pyramid of Giza had a base of 230.4 meters, and a height of 146.5 meters. A ping pong ball has a diameter of 40 millimeters. The volume of the Great Pyramid = (b^2 x h)/3 = (230.4^2 x 146.5)/3 = 2,592,276 cubic meters. The diameter of a ping pong ball is 40 millimeters = 0.04 meters, radius = 0.02 meters, volume = 4/3πr^3 = 4/3 x π x (0.02)^3 = 0.00003351 cubic meters. Spheres in a pyramidal container take up about 74.05% of the space (been there, done the math - see Thomas Hales' proof of the Kepler Conjecture). So, the final answer is 2,592,276 / 0.00003351 x 0.7405 = 57,283,807,162, or about 57 billion ping pong balls. Have I got this right?