[tex]Observatie!EOF=unghi~cu~varful~in~centrul~cercului\\
=\ \textgreater \ m(EOF)=EF(arc)\\
Fie~triunghiul~EOF(oarecare)\\
EF(baza)=4 \sqrt{5} cm\\
-------------\\
A= \frac{baza*inaltimea}{2} =\ \textgreater \ 4 \sqrt{5} = \frac{4 \sqrt{5} *OM}{2} \\
=\ \textgreater \ OM(inaltimea)=4 \sqrt{5} :2 \sqrt{5} =\ \textgreater \ OM=2cm[/tex]
[tex]ON(raza)^2=EF^2+OM^2\\
ON^2=16*5+4\\
ON^2=80+4\\
ON^2=84\\
ON=2 \sqrt{21} cm[/tex]
