# Finding Perimeter and Area in the Coordinate Plane

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## Objective

SWBAT use the distance formula to find perimeters and areas of geometric figures

#### Big Idea

It's Gridlock. Trapped inside the coordinate plane, armed only with coordinate pairs and formulas, students must find perimeters and areas of triangles and rectangles.

## Cooperative Activity

40 minutes

For this lesson, I divide students into groups of 3 to 4. Each student gets a straightedge, a calculator, a sheet of graph paper, and the Cooperative Activity_Perimeter and Area in the Coordinate Plane resource, and the Math Rubric. We review what it takes to get a 4 in each of the three rubric domains. I also explain that this section of the lesson will last 40 minutes and will be followed by a section in which students will have to solve similar problems on their own. Therefore, I explain, it is important to understand everything you do and retain it, not just complete it and forget it. So after I'm done preaching, I instruct students to get right to work on the assignment. Oh, one last thing, "Got questions?...read the directions"

During the activity I circulate the room making sure that students are engaged. This entails simple prompts to students like, "Explain to me what you're doing." or "How can you present your work in such a way that it would be self-explanatory to a 3rd person if they were reading your paper?"

At the end of the 40 minutes, I give students time to organize their work and get it ready for submission.

## Independent Practice

30 minutes

This section is pretty straightforward. Transitioning from the last section, I have the students rearrange the desks into rows since this is an independent activity. I also have to transition the energy in the room from a more relaxed cooperative atmosphere to testing conditions. No talking, no off task behavior allowed.

I review the requirements for scoring a 4 in each of the 3 domains on the math rubric and then students get started on the Independent Practice_Perimeter and Area in the Coordinate Plane resource.

When 30 minutes have elapsed, I collect the papers.

Time permitting, I review the solutions to the activity so that students get immediate feedback on their performance.