Solutio. 

 Sint, vt fupra, latera AB =za, BG=b, CDz:c, Tab - m . 

 DAr d, tura vero ponatur : Fi S * 2 - 



AP = AS —f s 

 BV = BQ.= a—fzzzzg, 

 Ca=CR = 5- g = h, 

 T>R = DSzzzzc — hzzzzl 



Vocetur porro radius circuii infcripti oP=:r, & du&is ex 

 centro o ad angulos re&is oA, oB, oC, oD, erit 



tang.lAz=L; tangJC = {jj 



tang.JBrzz^ tang. | D zz L • 



Cum igitur fit § (A -f- B-f-C -h D) = i$o , neceffe eft vt 

 fiat tang. |(A+B + C + D)z:o. At vero eft 

 tang.I(A + B)=)^z, 



tang.I(C + D)=z^4l, 

 Hinc fequitur fore 



o, 



jg — r r h i — r r 



ex qua aequatione adipifcimur radium circuli quadrilatero 

 A B C D infcripti 



1 /- fri(/-4-g)-K / g (ft-4-i ) 



quae expreffio, ob /-+- g zzzz a et h -\- i zzzz c , ad hanc con- 

 cinniorem reducitur : 



T ZZZZ V ~ nh ? ^~ r ^ 

 ' -a -i- q * 



Corollarlum i. 



$. 8-. Qiiod ad fuperficiem quadrilateri attinet, qnam 

 fupra chara&ere S defignaulmus , cuique obuium eft eam 



/ O 2 hic 



