The left and right focus F1, F2 of hyperbola x squared △ 25 minus y squared △ 9 = 1, the length of chord AB passing through F1 is 2, find the circumference of triangle abf2

The left and right focus F1, F2 of hyperbola x squared △ 25 minus y squared △ 9 = 1, the length of chord AB passing through F1 is 2, find the circumference of triangle abf2

The distance difference between a point and two focal points on the hyperbola is equal to the fixed length 2A,
There are: af2-af1 = 2A, bf2-bf1 = 2A; AF1 + af2 = 2
The sum of the two terms is af2 + BF2 = 4A + (af2 + BF1) = 4A + 2
a=5
:. L =AF2+BF2+AB=(4a+2)+2=4a+4=24