**ENGAGE**

As students enter the classroom, they should receive a group that tells where to sit with all needed materials available. Students should be informed that their mission today is to determine whether a pair of equations of lines is perpendicular.

**EXPLORE**

1. Student groups should trace the rectangular/square tile/object on a coordinate plane. Each group can decide to use a L shape from the graph to receive coordinate pairs to input into graphing calculator to generate equations of lines and graphs. Each group can also decide to use a triangle from the traced shape, use distance formula to calculate length values and then verify values as a Pythagorean triple.

2. The students should key their information into their graphing calculators (using the list key on the graphing calculator) to determine if the L shape of the traced object makes perpendicular lines and have perpendicular slopes. They should look for patterns, develop equations based on data and list slope conclusions based on data. The groups must agree on findings and be able to justify.

3. If students do not understand perpendicular lines and slopes, provide necessary feedback to move them forward with their thinking. Refer to : http://www.youtube.com/watch?v=VVvErpLG2EQ (if your school system does not allow youtube access, you may download the video using http://www.keepvid.com/)

Refer to https://www.khanacademy.org/math/algebra-basics/core-algebra-graphing-lines-slope/core-algebra-slope/v/slope-of-a-line

**EXPLAIN**

1. The teacher should be sure that students are using slope/distance or pythagorean theorem correctly to verify perpendicular lines.

2. Groups will discuss properties discovered and begin justifying their ideas; along with creating equations and graphs to match their tables in the calculator.

3. Allow students time to prepare attractive posters to share with class to begin discussions about perpendicular, along with having the groups share their findings using the Smartview function of the calculator.