The perimeter of a triangle is 104 units. The combined length of two of the sides of the triangle is 64 units. What is the length of the third side of the triangle in units?

Answer

Let x be the length of the third side of the triangle.
Set up an equation involving the perimeter of the triangle and solve for x: x + (the combined length of the other two sides) = 104. Substituting 64 for (the combined length of the other two sides) gives: x + 64 = 104.
Solve for x: x + 64 = 104, x = 40.