Please, help me to solve the problem:

Two fire towers are located 85 km apart on hills A and B. The bearing from A to B is north east. A fire F is observed from tower A at N10E and from B at N75W. The town at point C is on bearing of N25E from A and S70W from B. The observers report the wind is blowing the fire directly toward C at a rate 9km/h. How many hours do the officials have to evacuate the town?

I can't find the distance FC(Crying)

Thank you.