Let △ABC, AB=AC, the crossing vertex A is AD, BC is D,

(1) If AD=BD, AD=CD, ∴∠B=∠C=∠BAD=∠CAD,

That is, ∠ b = ∠ c = 180÷ 4 = 45, ∠ BAC = 90.

It is an isosceles right triangle.

(2) If AD=BD and AC=DC,

∴∠B=∠C=( 1/3)∠BAC，

That is, ∠ b = ∠ c = 180÷ 5 = 36, ∠ BAC = 36× 3 = 108.

(3) crossing the bisector with the bottom point b being ∠D, crossing AC over d,

If AD=BD=DC,

∴∠ABC=∠C=2∠A

That is, ∠ ABC = ∠ C = 180× 2/5 = 72, ∠ A = 36. ?

(4) Even BD(D is above AC), AD=BD, DC=BC, ∠ B = ∠ C = (540/7), ∠ A = (180/7).