Hi there! BF = 14
If AC = 19, the radius of circle C is 19.
In the picture we can see that AC = A F + CF.
Based on all the data we have we can fill in th: formula:
19 = A F + 12.
Subtract 12 from both sides.
7 = A F
A F = radius circle A = 7
BF, which is the diameter from circle A is two times the radius of the circle. Hence,
BF = 2 × A F = 2 × 7 = 14
~ Hope this helps you.
~ Note: there is a space between A F because the system doesn't accept is without a space (because of rude language).
