To determine if a triangle is isosceles, we need to check if at least two of its sides are equal in length. The given sides of the triangle are 9 cm, 8 cm, and 5 cm.
Since none of these sides are equal (9 cm ≠ 8 cm ≠ 5 cm), the triangle is not isosceles.
In summary, a triangle with sides measuring 9 cm, 8 cm, and 5 cm is not isosceles.