This activity is for use as a formative assessment tool after the introduction and overview of parallel and perpendicular slopes.
Before the Activity
Instruction before this activity is left up to the individual instructor. This activity is meant as a review before a quiz, test, or other formalized assessment.
During the Activity
In this activity center, the background is of a plaza in Rome. I have graphed an initial line that matches a walkway in the plaza. The students are sent the line as a background on their calcs. They are to contribute 3 lines; two that are perpendicular at different points, and one line that is parallel to the original (but not the same equation). I use this as a quick formative assessment after initial instruction and application of parallel and perpendicular lines in several settings, although this can also be used as an investigation into slopes as well.
After the Activity
I usually use worksheets after this activity that I have scanned in from the Ohio Achievement tests. I have not converted them into a file format that is recognized by the activities exchange, so I will update this later.