Perimeter of an isosceles triangle with a base of 7 cm and a side of 13 cm.

To find the perimeter of a triangle, you first need to understand what the perimeter is. The perimeter is the sum of all the sides of a shape, in this case an isosceles triangle.
The length of the AB (base) is 7 centimeters. Since the triangle is isosceles, its sides are equal to each other. This means that if the side of the triangle BC is 13 centimeters, then the other side AC is also 13 centimeters.
Perimeter formula: P = AB + BC + AC.
We get: P = 7 + 13 + 13 = 33 cm.
Answer: 33 cm is the perimeter of an isosceles triangle ABC.