Thesaurarium mathematicae, or, The treasury of mathematicks containing variety of usefull practices in arithmetick, geometry, trigonometry, astronomy, geography, navigation and surveying ... to which is annexed a table of 10000 logarithms, log-sines, and log-tangents / by John Taylor.

PROP. VII. Case 7. Two Sides and an Angle opposite to one of them gi∣ven, to find the Included Angle.

In the Triangle ADE, there is given the Side* 1.1 AE 70° 00', the Side ED 38° 30', and the An∣gle opposite thereunto at A 30° 28', and the Angle E is required.

First by Prop. 1. Case 1. I find the Angle D, opposite to AE, to be 130° 03', then proceed thus.

First find the Difference of the Angles, then find the Sum and Difference of the Sides.* 1.2 * 1.3

Now say,

As S. ½ X. cr^s. AE and ED 15° 45',

To S ½ Z. cr^s. AE and ED 54 15.

So is T. ½ X. of VV. D and A 49 47 30",* 1.4

To Tc. ½ V. at E 15° 47'. Which doubled is the Angle at E 31° 34', as was required.

Notes

• * 1.1

  Fig. 39.
• * 1.2

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• * 1.3

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• * 1.4

  Fig. 39.