# Drawing the Line

- Author:
- Jaime Dianzon, Tim Brzezinski

- Topic:
- Algebra, Coordinates, Linear Equations

## Where do you draw the line?

## OBJECTIVE: To graph a line on the Cartesian plane using points

There's a postulate in Geometry that 'two points determine a line.'
So if you're given two points, just plot them, draw a straight line passing through both points, and your job is done!
In previous exploratory activities, you've probably discovered how to do this.

*Taking the First Bite*(https://www.geogebra.org/m/ufyfkdr4)*Putting Things in Perspective*(https://www.geogebra.org/m/kxzydnyz)*Getting Off the Grid*(https://www.geogebra.org/m/hqa3etew)*Sharpening Your Tools*(https://www.geogebra.org/m/vjvjqs2z)*Standing at Sword's Point*(https://www.geogebra.org/m/un8uh2zr) You can also graph a line by constructing a table of values (at least two ordered pairs), plotting the points, and passing a line through them.*Toeing the Line*(https://www.geogebra.org/m/pfkb67ek) NOW ... instead of plotting randomly generated pairs of coordinates, you can use two special points—the*x-intercept*and the*y-intercept*. If the intercepts are not already given, you can easily derive them from the STANDARD FORM of a line*(*Ax + By = C) by using these formulas: x-intercept = C/A and y-intercept = C/B.*Traveling on the Standard Line*(https://www.geogebra.org/m/chu2bn3u) On the top left-hand corner of the applet below, you'll see a linear equation in STANDARD FORM. Use the following formulas to fill in the boxes: slope (m) = -A/B x-intercept = C/A y-intercept = C/B If you type in the correct values and your graph is correct, you'll see a big*sign appear. Repeat as many times as needed to master the concept.***"CORRECT !!!"**
The applet below is similar to the one above, except that the boxes for the slope and the intercepts have been left out.
Move the WHITE DOTS to graph the x- and y-intercepts.
If your graph is correct, you'll see a big

*sign appear. Repeat as many times as needed to master the concept.***"CORRECT !!!"**## TODAY you learned how to graph a line on the Cartesian plane using the intercepts.

In future lessons, you'll learn how to graph a line on the Cartesian plane using other sets of information. We hope you ENJOYED your GeoGebra adventure!