Ceva's Theorem

Ceva:=proc() local A,B,C,O,D,E,F:

D:=Pt ( Le (B,C)   ,   Le (A,O)):   E:=Pt (Le(A,C)   ,   Le(B,O)):   F:=Pt (Le(A,B)   ,   Le(C,O)):

ItIsZero ( DeSq(B,D)* DeSq(C,E)* DeSq(A,F)   -   DeSq(D,C)* DeSq(E,A)* DeSq(F,B)):

end: