The perimeter of an isosceles triangle is 28 cm, and the side is 10 cm. Find the base of the triangle.

Let an isosceles triangle ABC be given, with sides AB and BC and the base AC. By the condition of the problem, AB = 10 cm.

1) Find the side of the BC:

Since the triangle ABC is isosceles, it means AB = BC = 10 cm.

2) Find the base of the AC, based on the perimeter of the triangle (ABC = 28 cm):

AC = 28 -10 -10 = 8 (cm).

Answer: AC base = 8 cm.