A Vertical line is a straight line that runs from top to bottom or from bottom to top and is perpendicular to a surface, or another line considered the base.
For example, the y-axis in a graph is a vertical line because it stands upright and forms a right angle with the x-axis, which acts as the base. Vertical lines are often called standing lines due to their straight, upright position.Vertical lines are all around us in our everyday lives. You can see them in tall buildings, tree trunks, and table or chair legs. These are common vertical line examples in the real world.
In coordinate geometry, the slope of a line is calculated by dividing the change in the y-coordinate (rise) by the change in the x-coordinate (run). The x-coordinate stays the same for all points for vertical lines, meaning the change in x (run) is always 0. For example, if you consider a vertical line passing through x = 4, the x-coordinate remains 4 no matter the y value. As you move along the line, the y coordinate changes, but there is no change in the x coordinate. This results in a zero run, making the slope undefined. In other words, since there's no horizontal movement, the slope can't be calculated, that’s why we say the slope of a vertical line is undefined.
Difference Between Horizontal and Vertical Lines | ||
Aspects | Vertical Line | Horizontal Line |
Alignment | Runs parallel to the Y-axis | Runs parallel to the X-axis |
Slope | Undefined | Always zero |
Standard Form | Represented by x=a constant | Represented by y=a constant |
Direction | Moves from top to bottom, or bottom to top | Moves from left to right, or right to left |
Axis Intersection | Meets the X-axis at one specific point | Meets the Y-axis at one specific point |
Appearance on Graph | Straight line oriented vertically | Straight line oriented horizontally |
Examples | Equations include x=−2x or x = 7 | Equations include y= 3 or y=−6 |
Angle with X-axis | Forms a 90° angle | Forms a 0° angle |
Angle with Y-axis | Forms a 0° angle | Forms a 90° angle |
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