I. IN equal Circles (and so much more(a) 1.1 in one and the same) as the Radii or Semidia∣meters BC and bc are equal, so also it is evident, that the Right Sines DF & Df, of equal Arches BD and bd, or equal Angles BCD and bcd, also the Tangents BE and be, and Secants CE and ce, and Subtenses or Chords DG and dg, also the Sagittae or intercepted Axes BF and bf, of double the Arches DBG and dbg, &c. will be equal, and so consist of an equal number of Parts of the whole Sine or Radius, &c. which both is evident from what we have said before, and may be further evinced, if one Circle be con∣ceived to be put on the other, and the Radius BC on the Ra∣dius bc, that so they may coincide, by reason of the equality of the Arches BD and bd; and so of all the rest. And è contra,
II. In unequal Circles, the Sines, Tangents, &c. of equal Angles BCD or bcd (Fig. 14.) or similar Arches, or Arches of an equal number of Degrees, BD and bd, will be also simi∣lar or like, &c. i. e. the Sine df consists of as many parts of its Radius bC, as the Sine DF does of its Radius BC, &c. e. g. if the Radius BC be double of the Radius bc, each thousandth part of the one, will be double of each thou∣sandth