It is known that the hyperbola (X & # 178; / 4) - (Y & # 178; / 8) = 1, the two ends a and B of the chord passing through the left focus F1 are on the left branch, and | ab | = 6, F2 is the right focus, find the perimeter of △ abf2

It is known that the hyperbola (X & # 178; / 4) - (Y & # 178; / 8) = 1, the two ends a and B of the chord passing through the left focus F1 are on the left branch, and | ab | = 6, F2 is the right focus, find the perimeter of △ abf2


a²=4
On the left branch, af2-af1 = 2A = 4
BF2-BF1=2a=4
Add
Because AF1 + BF1 = AB = 6
So af2 + BF2 = 8 + 6 = 14
So perimeter = 14 + 6 = 20