[ 9 2 5 1 
twice the fine of half the arch GF, and GB twice 
the fine of half the angle ACB to the r ^ dlus of ^ 
circle GBD, wh ich is half G D j fin. AC x lin. >C 
is to rad. q as lin. | ED — B C x lin. 7 E D AC 
to fin. i ACB I’. And this is Napeir’s firft method 
of finding an angle from the three fides given (e), as it 
is ufually delivered. , . ^ „ r . , 
Again, AK is to DG, or AK x DG to DG , as 
AK x DH (ED x DF) to DG x DH.oi Db . 
Therefore, D B being twice the fine of ha f the angle 
B C D, or twice the cofine of half the angle AC B to 
the radius of the circle GBD, as fin. t ~ x irh — 
to rad.s fo is T E D X fin. i E D - A B to cof. 1 ACBIV 
And this is Napeir’s fecond method (/ ). 
And laftly, the cofine of an arch or angle being 
to its fine, as radius to the tangen t, hn. — u 
x fin. 4- E D — A B will be to fin. fED-BC 
x fin. }ED — AC as rad. q to tang. \ ACBl q , which 
is a third method added by Gellibrand (&)• 
Moreover, 
In plain triangles, from the three fides given may 
an angle be found by a procefs fimilar to each ox 
thefe, as follows : 
(*) Mirific. Canon. Log. defcrip. lib. ii. c. 6. § 8. 
(/) Ibid. § 9. 
U) Trigon. Britan, p. 75. 
6 C 2 
In 
