A line and a circle intersect at $A$ and $B,$ as shown below. Find the distance between $A$ and $B$. The line is x = 4, and the equation of the circle is x^2 + y^2 = 25.
x^2 + y^2 = 25
(4)^2 + y^2 = 25
y^2 = 9
y = -3 y = 3
A= (4,-3) B = (4,3)
AB = (3 - -3) = 6