Traditional Culture Encyclopedia - Photography major - (20 14? As shown in the figure, in the plane rectangular coordinate system, point A is the intersection of the parabola y=a(x- 1)2+b and the Y axis, and point B is on this parabola.

(20 14? As shown in the figure, in the plane rectangular coordinate system, point A is the intersection of the parabola y=a(x- 1)2+b and the Y axis, and point B is on this parabola.

Solution: the symmetry axis of parabola y=a(x- 1)2+b is x= 1,

If CD⊥AB is at point D, then AD= 1,

Then AB=2AD=2,

Then AB is equilateral and the circumference of △ABC is 3× 2 = 6.

So the answer is: 6.