t 282 ] 
2. c X cofin. a 4- ^ X coL -j - 0 ) -f. c x col. (« + 13 + y}+ <5^ X cof. (« + /3 -f- y -f J) 
-j* f X cof. (*4-^4->'4-^4-E^-i-yx col. ®4"/3-|-y4''^4"* + Cj — 
In fa6l it is fin. (/3' + |S + y + J'+f+<^) = fin. 360° = 0, 
and cof. (<3^ + /S + ^ + J'+e + ^) = + i.; but in order to give 
the fame form to the two expreflions, I rather chofe to 
reprefent them as I have done. By means of thefe two 
theorems the folution of polygons will be as eafy as that 
of triangles by common trigonometry. 
XXVI. Jn 
