198 The general 5e 7 the cu N 5. 0HAP. III.

Concerning tlie joyni Uſe of, the Lines of Numbers, Sintsand Tang ents. 0 f 8

OC the joynt Ulſe of the Lines of Numbers, Sines and

Tangents, I ſhewed how they might ſerve for the Reſolutionof Right-lined Triangles, whereof I ſet down five Propoſitionsin che nineth Chapter of the firſt Book of the Croft. ftaſf. And theſealſo may be applied co the Table and Canon of Logarithms. fThe Sides of cheſe Triangles are meaſurecd by ablolute Numbers,and ſo repreſented by Logarithms. 5 6Ih!be Angles are meaſured by degrees and minutes, andd ſo to be found 2by Sines and Tangents in the Canon. f*

—

PRO P. I. 5 iHaving three Angles and one Side, tb find the other two Fides.

T. it be a Rectangle Triangle, wherein one Side about the riglit Anglebeing known, it were required only to find the other, this might bereadily done by Sines and Tangents. As in the Rectangle A I B, Know-ing the Angle B AI to be 43 gr. 20 1. and the Side A I f be 244, ifit were required to find the otfier Side A I.

As ibs Radius(the Tangent ef) 45 gr. Oo n. 10. oo5 5 i——I to the Jangent of the Angle 43 30 9.9749 195So the Side piuen AI 244 2.3 873898To tbe Side regaired BI„ 132.3621093

Fut where both the other Sides are required, it is beſt done by Loga-rithms and ines. As in the ſame Rectangle AI B, having the chreeAngles and the Side AI, to find both BI and A B.

A.