∴DB=DC= 1/2AB
Ad divides the circumference of triangle ABC into 3 and 4 parts.
∴(ab+ 1/2ab):( AC+ 1/2ab)= 3:4
∴4(ab+ 1/2ab)=3( AC+ 1/2ab)
AB=2/3AC
Or ∴ (ab+1/2ab): (AC+1/2ab) = 4: 3.
∴3(ab+ 1/2ab)=4( AC+ 1/2ab)
AB=8/5AC