(A;B;C;D) i.p. (1/2;1/3;1/6;1/7) [A:(1:1/2)=A:2 ... ]
⇵
A/2=B/3=C/6=D/7 ... =k siind ca , suma unghiurilor
in patrulaterul convex este
A+B+C+D=360°
⇵
A = 2k; B=3k ; C=6k si D=7k inlocuim ⇵
2k+3k+6k+7k=360°
k=360:18=20
⇒ m(< A)=2×20°=40° ; m(< B)=60° ; m(< C)=120° si m(< D)=140°