messer

1. Here is our first slope investigation:

@http://teachers.henrico.k12.va.us/math/HCPSAlgebra1/Geogebra/slope_practice1.html

Please play with this applet and record your answers to questions 1-3 in your notebook.

2. To review how to calculate slope between two points by hand, please go here:

@http://www.algebasics.com/3way11.html

Do the 7th, 8th, 9th, and 10th questions on the left in your notebooks. To check your answers (or get help with how to do a question), just click on the question. Since the explanations require sound, you should use earphones or go to a quiet place in class to listen. You can also fast-forward to the answer.

3. Open the application Geogebra on your laptop. Select View-Grid and create a line through the points (2, 1) and (6, 6). Use the **Slope** tool within Geogebra (one of the tools across the top) to calculate the slope of the line. Who can figure out how to do this first?!?

4. Now create a line through the point (2, 6) that is **parallel** to your line from question 3. Use the **Slope** tool within Geogebra to calculate the slope of the line. How should the slopes of the two lines compare? Adjust your line if necessary. Complete the following statement in your notebook: **When two lines are parallel, their slopes are .**

5. Now take your line from question 4 and change it so that it still passes through (2, 6) but is now **perpendicular** to your line from question 3. To check that your lines are really perpendicular, first use the **Intersect two objects** tool within Geogebra to create an intersection of the two lines, and then use the **Angle** tool to select a point on one line, the intersection point, and a point on the other line to measure the angle between the two lines. Adjust your line if necessary. Use the **Slope** tool to calculate the slope of your perpendicular line. Do you see a connection between these two slopes (or do you remember a connection from a previous course)? Complete the following statement in your notebook: **When two lines are perpendicular, their slopes are****.**

6. Do the practice worksheet from Mrs. Messer. Finish for homework.