The perimeter of the triangle is 1.8 dm, and the lengths of its two sides are equal to 0.5 dm

The perimeter of the triangle is 1.8 dm, and the lengths of its two sides are equal to 0.5 dm. Find the length of the third side of the triangle.

We denote by x the length of the third side of this isosceles triangle.
According to the condition of the problem, the lengths of the other two sides of this isosceles triangle are 0.5 dm, and the perimeter of this triangle is 1.8 dm, therefore, we can draw up the following equation:
x + 0.5 + 0.5 = 1.8.
We solve the resulting equation and find the length of the third side of this triangle:
x + 1 = 1.8;
x = 1.8 – 1;
x = 0.8 dm.

Answer: The length of the third side of this triangle is 0.8 in.