14 looks to long and complicated to come up, what other ones are likely to come up?
19 has come up twice in the past few years meaning that it is less likely to come up. Hopefully it'll be 4,6 or 9 but that seems to be unlikely. We'd be so unlucky if we did get 14.
its either going to be 14 or 19, bu most likely 19
I think that it may be theorem 14. I found this video very helpful when studying the theorem. The only thing that he doesn't explain is why triangles ACB and ADC are similar. But this will only be worth a couple of marks in the exam. Here is the link to the video:
Hope this helps :)