To find the perimeter of the square, we multiply the length of one side by 4 since a square has four equal sides. Therefore, the perimeter of the square is 4 * 2x = 8x.
To find the perimeter of the equilateral triangle, we multiply the length of one side by 3 since an equilateral triangle has three equal sides. Therefore, the perimeter of the triangle is 3 * (2x + 13) = 6x + 39.
Since the square and the triangle have the same perimeter, we can set up the equation:
8x = 6x + 39
Subtracting 6x from both sides, we get:
2x = 39
Dividing both sides by 2, we find:
x = 19.5
Therefore, the value of x is 19.5.