The description and use of the universall quadrat.: By which is performed, with great expedition, the whole doctrine of triangles, both plain and sphericall, two severall wayes with ease and exactness. Also the resolution of such propositions as are most usefull in astronomie, navigation, and dialling. By which is also performed the proportioning of lines and superficies: the measuring of all manner of land, board, glasse; timber, stone. &c. / By Thomas Stirrup, Philomathemat.

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Title: The description and use of the universall quadrat.: By which is performed, with great expedition, the whole doctrine of triangles, both plain and sphericall, two severall wayes with ease and exactness. Also the resolution of such propositions as are most usefull in astronomie, navigation, and dialling. By which is also performed the proportioning of lines and superficies: the measuring of all manner of land, board, glasse; timber, stone. &c. / By Thomas Stirrup, Philomathemat.
Author: Stirrup, Thomas.
Publication: London :: Printed by R. & W. Leybourn, for Tho. Pierrpont, at the Sun in Pauls Church-yard,; 1655.
Rights/Permissions: To the extent possible under law, the Text Creation Partnership has waived all copyright and related or neighboring rights to this keyboarded and encoded edition of the work described above, according to the terms of the CC0 1.0 Public Domain Dedication (http://creativecommons.org/publicdomain/zero/1.0/). This waiver does not extend to any page images or other supplementary files associated with this work, which may be protected by copyright or other license restrictions. Please go to http://www.textcreationpartnership.org/ for more information.
Subject terms: Astronomy; Dialing; Geometry; Navigation; Trigonometry
Link to this Item: http://name.umdl.umich.edu/A93912.0001.001
Cite this Item: "The description and use of the universall quadrat.: By which is performed, with great expedition, the whole doctrine of triangles, both plain and sphericall, two severall wayes with ease and exactness. Also the resolution of such propositions as are most usefull in astronomie, navigation, and dialling. By which is also performed the proportioning of lines and superficies: the measuring of all manner of land, board, glasse; timber, stone. &c. / By Thomas Stirrup, Philomathemat." In the digital collection Early English Books Online 2. https://name.umdl.umich.edu/A93912.0001.001. University of Michigan Library Digital Collections. Accessed June 10, 2024.

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CHAP. LII. By knowing the base and one of the sides, to finde the other side, with both the oblique angles.

THus in the right angled triangle ABC, having the base AC 65 deg. 23 min. and the side BC 33 deg-36 min. we may finde the other side AB, and the two oblique angles at A and C.

For if you count the base AC 65 deg. 23 min. upon the Horizon, and the side BC 33 deg. 36 min. among the parallels; and then move the planisphere to and fro, until the 65 deg. 23 min. do cut the parallel of 33 deg. 36 min. counted from the Equinoctial, and there shall meet you the 60 meridian to make up your triangle; which 60 degrees is the required side AB, and now at this very instant you may see the Horizon cut the limbe at 37 deg. 30 min. which is one of the angles required, viz. the angle BAC. And now for to finde the other angle you must shift the sides as in the last Chap. for the side subtending the angle required, must be counted a∣mong the parallels.

Thus moving about the planisphere til the intersection of the sixtieth parallel and meridian of 33 deg. 36 min. do cut the Horizon, which will be at 65 deg. 23 min. the base AC as before, and now doth the horizon cut the limbe at 72 deg. 16 min. which is the angle ACB as was required.