What is the distance between points A 1 2 3 and B 4 5 6?

The three-dimensional Pythagorean theorem yields a formula for the distance between two points (x1, y1, z1) and (x2, y2, z2) in space:

d = √[(x2 - x1)2 + (y2 - y1)2 + (z2 - z1)2] = √[(4 - 1)2 + (5 - 2)2 + (6 - 3)2] = √(32 + 32 + 32) = √27 = 3√3 ≈ 5.2