Given that a and B are the lengths of two sides of an isosceles triangle, a and B satisfy B 2 + a − 1 + 4 = 4b, the perimeter of the triangle can be obtained

Given that a and B are the lengths of two sides of an isosceles triangle, a and B satisfy B 2 + a − 1 + 4 = 4b, the perimeter of the triangle can be obtained

∵ B2 + a − 1 + 4 = 4b, ∵ (b-2) 2 + a − 1 = 0, ∵ B-2 = 0, A-1 = 0, the solution is b = 2, a = 1. ① when the base length of the isosceles triangle is 1, the perimeter of the triangle is 2 + 2 + 1 = 5; ② when the base length of the isosceles triangle is 2, 1 + 2 = 2, it can not form a triangle. To sum up, the perimeter of the triangle is 5