RESPONSrO Ai) QUAfiSTIONEM MATHEMATICAIM» 



- . _ Cos. AFG Cos. 36° 



Cos. ALr = — ;, . ,. =: -r^ i— . 



Sin. FAG bm. 60° 

 Latus Dodecaedri = 2 Sin. AG = 2. yi — Cos*. AG " 



= .//,- *tt/5+.y 



= =//. 



*— A CVs+^v^s) 



4 



= ^[/'-^'r^ 



-l/ 



3 — 1/5 



Igitur latiis Dodecaedri = r/ pLl — a, brevitatis causa. 



Dodecaedrum dividi potest in 12 piramides quinquangulares. In basi itaque ABCDEH 

 est AHB = 72°, HAB = 54°. Ducatur perpendicularis HK, fit AHK = 36° et AK» 

 = 9°°- -IGOCiA ^i-nKi.f 



HK = AIC . Tang. HAK = -^ •^'"- "^^ 



Cos. HAK ■ • -- . 



_ t a ■ Sin. 54° _ ia . 4(^50.1) 



Fia 7 SiD. 36^ ~ I , 



2V^2 ^ "^ ^ 



21/2.// 5^:^175 -*'^// 5-^ 



Sin. 36° - _!_ __7-^ - ^5—^5 

 HO = l/KO^ — AH-" 



. . // 2(6-21/5) 



= A/,_ _2fl_ = A/ ,_ 3- ' nam^=/X 



■_./y g-2v^5 



ViS* '" ■ ^ 3 



3(5 — 1/5) 



AO 



