In simple terms, the absolute value of a number is its "
distance" from the number
0.
With real numbers, this is quite simple, but when you have the
"2-dimensionality" of a complex number (represented as a + bi, where
ii=-1), you must use the pythagorean theorem to find
the hypotenuse, which is the distance from 0.
|a + bi| = sqrt(aa + bb)