Horizontal lines have a slope of zero, and run parallel to the x axis. Vertical lines have a undefined slope, and run parallel to the y axis. The equation for a horizontal line equals y=c, and the equation for a vertical line equals x=c. If a horizontal line crosses a vertical line the two lines would be perpendicular to one another.
A Horizontal Line is a line that goes straight from<em> left</em> to<em> right</em> (or right to left) parallel to the x-axis of the coordinate plane. All of the points on the line will have the same y-coordinates.
<h2>What is a Vertical Line?</h2>
A Vertical Line is a line that goes straight up and down Parallel to the y-axis of the coordinate plane. All of the points on the line will have the same x-coordinates.
<h3>Commonality: Any vertical line is defined as perpendicular to any horizontal line. </h3>
