thanks for any hints.
P18 is one of the harder problems. There is a typo in the question (hopefully already corrected, but put here just in case): $G$ in the question should be $F$. It takes some work, but eventually we want to find the ratio $BF/FC$.
Could you please give some hints on how to find this ratio? thanks
BTW, I found FBD to be identical as AOB and many similar triangles but still got stuck in finding the ratio.