The inequality \( x \leq 1 \) in interval notation is \( \square \).

The inequality \( x \leq 1 \) in interval notation is expressed as \( (-\infty, 1] \). This indicates that \( x \) can take any value less than or equal to 1, extending infinitely to the left on the number line. When graphing this inequality, you would use a closed circle at 1 to show that 1 is included in the solution set, and a line extending leftward to indicate all numbers less than 1 are also included. This visual representation helps in understanding the scope of the solution!