minimiim duodecim laciniae in polis conciirrere debeant, 

 id quod plerumque fmc infigni vitio vix praeftare licet. 



..bjji'. §• ^^' Operae igitur pretium erit inueftigare, quam 

 txaSie duodecim illa pentagona, in quae fuperficies globi ab 

 inrcripto Dodecaedro diuiditur, figuris planis obduci queant; 

 Hunc in finem primo omnes dimenfiones vnius pentagoni 

 fphacrici accurate determinemus, vbi quidem fufiiciet vni- 

 cum fecT:orem A O B condiderafle , exiftente (cilicet ccn- 

 tro talis pentagoni in pundo O, et radio fphaerae ma- 

 nente perpetuo — r. Hic igitur demiflb perpendiculo O P 

 crunt anguli a =i 60" et (3 zr 36° , area vero talis pen- 

 tagoni fupra eft iiiuerita ^^ — 1,04.71975. rr : tantam 

 igitur etiam aream figura plana inducenda recipere de- 

 bebit. 



f 27. Nunc more follto triangulum fphaericnm 

 AOP euoluamus, ope formularum cof A P zi: ^^^ et 

 coL O A — cot. a. cot. |3 



a /.cof. grz: 9,9079575 ad. /. cot. S =: 10,1387390. 

 fubtr. /. fin. a — 9,9375306 adde /. cot. a r: 9^ <5i4394 



/.cof. APrr 9,9704270 "•-"'^.'cofOA:: 9,9001784 

 crgo AP— 20°. 54'. 19" hinc O A - 37°. 22'. 38' 



fiveAP:=:75 2 59" fiue O A = ^ i 34558" 



ad. /. AP =1:4,8765584 ad. /. OA- 5,1^89095 



adde =4,6855749 adde - 45<5855749 



9,5621333 9^8144844 



ArcusAPz=o,364866o.r Arcus 0^ = 0,6523556.?- 



§. 28. 



