Students will investigate characteristics of perpendicular lines by creating sets of perpendicular lines and recording information about each set of lines.

Basic Set – Up:
1. Open Geogebra.
2. On the top menu, click options, and set ROUNDING to 15 Decimal Places.
3. Below the pointer, click the arrow beside ALGEBRA. On the drop down menu, click the first image.
Investigation:
1. Place a point on the x-axis.
2. Place a point on the y-axis.
3. Draw a line between the two points.
4. Draw a perpendicular bisector between the created line.
Record Information:
1. On the left side of your screen, Geogebra has recorded the equations of the two lines you have created.
2. Click on the equation of the first line.
3. When the equation is highlighted, right click and convert the equation of the line to y = mx + b.
4. Convert the equation of the second line to y = mx + b form.
5. Record the equations of the lines in the chart below.
6. Convert the slopes in equation from decimal to fraction form and record in chart.
a. To use Geogebra:
i. In the input bar (bottom of screen), type FractionText[ <Number> ] with <Number> replaced with the decimal you wish to convert to a fraction.
ii. Hit enter.
iii. On the left side of your screen under “text”, the fraction form of the decimal will appear.
iv. Record equation with slope as a fraction in the chart attached.
7. Repeat the steps in Investigation and Record Information for 5 pairs of perpendicular lines.