Calculate the height of an isosceles triangle if its perimeter is 18 cm.

There is not enough data in the condition to solve this problem. The height of an isosceles triangle can be found by the Pythagorean theorem: h ^ 2 = a ^ 2- (b / 2) ^ 2. where a is the side and b is the base. Also, the height of an isosceles triangle can be found by Heron’s formula: h = 2√ p (p-a) (p-b) (p-a) / b, where a is the side, b is the base, and p is the semiperimeter, which is p = 1/2 * (a + b + a). Thus, to calculate the height of an isosceles triangle, you need to know the lengths of its sides. If the length of either the side or the base were given in the condition, then all sides could be calculated along the perimeter.