To find the value of \( x \), we start with the formula for the perimeter of a square, which is given by:
\[ P = 4s \]
where \( s \) is the length of one side of the square. In this case, the perimeter \( P \) has been given as:
\[ 10x + 26 \text{ ft} \]
We also know that the perimeter is equal to 144 ft. Therefore, we can set up the equation:
\[ 10x + 26 = 144 \]
Next, we will solve for \( x \):
- Subtract 26 from both sides:
\[ 10x + 26 - 26 = 144 - 26 \] \[ 10x = 118 \]
- Now, divide by 10 to isolate \( x \):
\[ x = \frac{118}{10} = 11.8 \]
Thus, the value of \( x \) is:
\[ \boxed{11.8} \]