The American house-carpenter; a treatise on the art of building, and the strength of materials (1867)
Hatfield, R. G. (Robert Griffith), 1815-1879 · New York, J. Wiley · leaf 85
on the same chord, df are equal. Theangles G and A being right angles, {Art. 156,) are likewiseequal. iNow, since A equals (7, and B equals D^ thereforethe sum of A and B^ equals the sum of G and I)—or the anglea cf equals the angle c nf. 164.—Proposition. Two chords, a h and g d^ {Fig-… … Fig. 115. equal to the product oi a e multiplied \>j eh. The triangle Ais similar to the triangle i?, because it has corresponding an-gles. The angle i equals the angle e, (Art. 148 ;) the angle atG equals the angle at a because they stand upon the samechord, d 5, {Art 161;) for the same reason…
Carpentry · Architecture
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![An illustration from Nicolai Copernici Torinensis De reuolutionibus orbium coelestium, libri VI : Habes in hoc opere iam recens nato, & aedito, studiose lector, motus stellarum, tam fixarum, quàm erraticarum, cum ex ueteribus, tum etiam ex recentibus obseruationibus restitutos: & nouis insuper ac admirabilibus hypothesibus ornatos. Habes etiam tabulas expeditissimas, ex quibus eosdem ad quoduis tempus quàm facillime caculare poteris. Igitur eme, lege, fruere. [Line in Greek] (1543)](https://img.insideoutlibrary.com/img/200/ia-nicolaicopernici00cope-309-202.webp)
