Answer:
13.9
Step-by-step explanation:
First we find the hypotenuse of triangle of BCF. which is 14.3178. Now we have 2 sides of triangle ABF.
[tex]20^{2}=14.3178^{2}+AB^{2}[/tex] to solve AB
AB is [tex]\sqrt{195}[/tex] or 13.964
