In the triangle ABC, ab = AC, D is the midpoint of AB, de ⊥ AB intersects AC at point E, the circumference of the triangle BCE is known to be 10, and ac-bc = 2, so the circumference of the triangle EBC can be obtained

In the triangle ABC, ab = AC, D is the midpoint of AB, de ⊥ AB intersects AC at point E, the circumference of the triangle BCE is known to be 10, and ac-bc = 2, so the circumference of the triangle EBC can be obtained

For what?