\begin{tabular}{l} Select the answer that best completes the given statement: \\ The slope of a vertical line is \\ my instructor \\ undefined. \\ \hline one. \\ \hline negative. \\ \hline positive. \end{tabular}

Did you know that a vertical line has an undefined slope because the change in x (the horizontal distance) is zero? This means you’d be dividing by zero if you were to calculate the slope using the formula (change in y) / (change in x). Since division by zero is a big no-no in mathematics, we say the slope is undefined! In real life, vertical lines can represent situations where one variable remains constant regardless of the value of the other. For instance, think of a building’s height — no matter how far away you are, the height remains constant, resulting in a vertical line on a graph representing height versus distance. Isn’t that a fascinating way to see these concepts reflected in the world around us?