Section 9
![Proposition 51, Theorem 39](/covers/principia.jpg)
Section 9
Proposition 51, Theorem 39 →
![Proposition 52, Theorem 40](/covers/principia.jpg)
Section 9
Proposition 52, Theorem 40 →
![Proposition 53, Theorem 41](/covers/principia.jpg)
Section 9
Proposition 53, Theorem 41 →