Answer: The third side measures 24 cm
Step-by-step explanation: An isosceles triangle is that which has two sides and two angles having equal measurement. Hence, two sides of the triangle will have the same length, while the third side will have a different measurement. Now we have an isosceles triangle with one of the two equal sides given as 13 cm. That simply means the other equal side measures 13 cm.
Remember that we have been given the perimeter of the triangle already. The perimeter of a triangle is simply the addition of all three sides of the triangle.
We can now derive the following expression from what we have so far;
Perimeter = A + B + C
(Where A, B and C represents the three sides of the triangle)
Hence, the expression now becomes
Perimeter = A + B + C
50 = 13 + 13 + C
50 = 26 + C
Subtract 26 from both sides of the equation
50 - 26 = 26 - 26 + C
24 = C
Therefore, the third side of the triangle is 24 cm