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A number line looks just like a simple cross.Ryan McVay/Photodisc/Getty Images
Draw a number line. All number lines look just like a simple cross with one long vertical line (the y-axis), intersected with a horizontal line in the middle of the y line (the x-axis). Number your drawing. The zero point is represented at the intersection of the x and y axes -- the middle of your cross. Numbers to the left of zero are negative and numbers to the right are positive for the x-axis. For the y-axis, the negative numbers are below the zero and the positive numbers are above the zero. The four sections are known as quadrants. Quadrant one is northeast, quadrant two is northwest. Quadrants three is southwest, and four is southeast. - 2
Your line will look like this.Ryan McVay/Photodisc/Getty Images
Graph your line. All points on a line are described with the x coordinate first, followed by the y coordinate (x,y). The first point for this example is (-22, 14) and your next point is (10, 26). The first point of your line would be in quadrant two and the last point point would be in quadrant one. Draw a line connecting your two points. - 3). Calculate the average between the points. Add your two x values (-22 + 10) and divide by two. Your middle x point is -6. Do the same for your y points by adding 26 and 14 together to get 40, dividing by two. Your middle y point is 20. The midpoint of your line is (-6, 20).
- 4). Graph the midpoint on your number line. In this example, the midpoint, (-6, 20) is in quadrant two. Any line with a beginning and an endpoint has to have only one midpoint. You cannot calculate the midpoint if you do not have the beginning and endpoints of a line; however, you can calculate the midpoint of any section of a line using the same methodology.
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