For the numbers 3, 4, 5, which represent the sides of the Pythagorean triangle, also denote the intervals of the scale.
The terms used in the statement of the problem may be explained as follows.

A perfect number (Greek), as already stated, is one which is equal to the sum of its divisors.

Thus 6, which is the first perfect or cyclical number, = 1 + 2 + 3.

The words (Greek), 'terms' or 'notes,' and (Greek), 'intervals,' are applicable to music as well as to number and figure.

(Greek) is the 'base' on which the whole calculation depends, or the 'lowest term' from which it can be worked out.