Commentary on Proposition VII.5

Back to Proposition VII.5.

[Folio 0310 | p. 304]

If

$$a = \frac{1}{n}b, \text{ and } c = \frac{1}{n}d, \text{ then}$$

$$a + c = \frac{1}{n}(b + d).$$

The proposition is of course true for any quantity of pairs of numbers similarly related, as is the next proposition also; and both propositions are used in the extended form in VII. 9, 10.