LetAB+BC+AC=2P.

PXP-AB: P-AC x P-BC:: Rq: Tq, & C, and hence Cis known. (5.) Otherwise,

Let AD be perpendicular to BC. 1. If ABq be less than ACq+CBq. FIG. |16. BC: BA+AC:: BA -AC: BD- DC, and BC the sum of BD, DC is given; therefore each of them is given. (7.)

2. If ABq be greater than ACq+CBq. FIG. 17.BC: BA+AC: BA-AC: BD + DC; and BC the difference of BD, DC, is given, therefore each of them is given. (7.)

And CA: CD:: R: CoS, C. (1.) and C being found, A and B are found by case 2 or 3.