[81.] Problem VIII.
[82.] To do this another Way.
[83.] Demonstration.
[84.] Problem IX.
[85.] Problem X.
[86.] Demonstration.
[87.] EG: EN:: GY: NM.
[88.] Definition.
[89.] Problem XI.
[90.] Lemma.
[91.] Demonstration.
[92.] Remarks.
[93.] Problem IX.
[94.] Operation.
[95.] Demonstration.
[96.] Problem X.
[97.] Operation.
[98.] Demonstration.
[99.] Remarks.
[100.] Method II. 70. By the accidental Point of inclin’d Lines.
[101.] Operation.
[102.] Demonstration.
[103.] Method. III.
[104.] Operation.
[105.] Method IV.
[106.] Prob. XIV.
[107.] Example I.
[108.] Example II.
[109.] Conclusion.
[110.] CHAP. IV.