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. VI. Case 6. Two Angles and a Side opposite to one of them gi∣ven, to find the third Angle.

In the Triangle ADE, there is given the An∣gle* 1.1 A 30° 28', the Angle D 130° 03', and his opposite Side AE 70° 00', and 'tis required to find the Angle at E.

First by Prop. 2. Case 2. I find the Side DE, opposed to the Angle A; to be 38° 30', then proceed thus.

Fi••st find the Sum and Difference of the Sides. Then find the Difference of the Angles.* 1.2 * 1.3

Now say,

As S. ½ X. cr^s. DE and AE 15° 45',

To S. ½ Z. cr^s. EA and DE 54 15.

So is T. ½ X. VV. D and A 49 47 30",

To Tc. ½ V. at E 15° 47' 00". which doubled giveth the Angle at E 31 34, as required.

Notes

• * 1.1

  Fig. 39.
• * 1.2

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• * 1.3

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