No, horizontal lines do not have an undefined slope. In fact, horizontal lines have a slope of zero.
Here’s why: The slope of a line is a measure of its steepness and direction. It is calculated as the change in the y-coordinate divided by the change in the x-coordinate between two points on the line. For a horizontal line, the y-coordinate remains constant, meaning there is no change in the y-coordinate (Δy = 0). Therefore, the slope (m) is calculated as:
m = Δy / Δx = 0 / Δx = 0
Since the slope is zero, horizontal lines are considered to have a zero slope, not an undefined one. An undefined slope occurs in vertical lines, where the x-coordinate remains constant, leading to a division by zero in the slope formula.