The svrveyor in foure bookes / By Aaron Rathborne.

  • Aaron Rathborne
Date:
1616
Catalogue details

Licence: Public Domain Mark

Credit: The svrveyor in foure bookes / By Aaron Rathborne. Source: Wellcome Collection.

    22/252 page 8
    ss centre to the former points B. and C. then is that angle faid to be inthe centre of a circle, iy asthe angle B. E.C. Which angle likewife fubtendeth the fame circumference B. D.C. and is alwayes double in quantitie to the former angle , drawne from the circumfe- rence. And the circumference B, D.C. isal- fo the meafure of the quantitie or greatnefle of theangle B. E, C. in the centre. DEFIN. XIX, Enc. 3. Def.9. Ram.16.3. Euc.t. from the centre of a Circle, and vnder part of the circamference receined of them, Sin the lat De rrN1110N,the figure B.E.C. is the Sector of a Ae. becaufe it is contained vnderthe two right lines E.B.and B.C. drawne from the centre E. and vnder part of the circumference, namely, B. D. C. receiued of them. D BRFUN, os se Right lined figures are fuch, as are contained bnder right lines, of what number foener, aboue two, S thofe which follow, being contained vnder three, foure, fine, or Avr fides, who take their denominations, as well of the number of their angles, as of their fides; fo a figure contained vnder three lines, in refpect of his fides, is called a three fided figures and in refpe& of his three angles is called a Triangle: and fo of thereft. Where is to be noted, that euery right lined figure hath as many angles as tt hath fides. DeFins XXL An Equilater Triangle ts that, which bath three equall fides, Sa Triangle isthe firft ofall right lined figures (for vnderleffe then three right lines can no figure be contained:) So of all Triangles, the Equilaterall Triangle is moft fimple and abfolute, hauing equall lines and equall angles ; containing euery of them a Sextans of a Circle, which is 60 degrees. Triangles haue their denominations, difteren- ces,and appellations,as well of their angles as their fides: As this Triangle A. in refpect of his
    digitised image 1
    digitised image 2
    digitised image 3