Lesson 13
Perimeter and Area of Rectangles
Lesson Purpose
Lesson Narrative
The purpose of this lesson is to plot the lengths and widths of different rectangles with a given perimeter or with a given area. In a previous course, students found rectangles with the same area and different perimeter and rectangles with the same perimeter and different area. Graphing the possible lengths and widths helps to visualize and quantify these relationships. Specifically, when the perimeter is given, the relationship between the length and width is that each unit taken away from the length is added to the width. When the area is given, the relationship is more complicated and the graphs of the two situations reveal this. As students calculate side lengths they also have opportunities to perform arithmetic with fractions and decimals.
 Representation
 MLR8
Learning Goals
Teacher Facing
 Use the coordinate grid to understand the length and width of rectangles with fixed area.
 Use the coordinate grid to understand the length and width of rectangles with fixed perimeter.
Student Facing
 Let’s explore the perimeter and area of rectangles on the coordinate grid.
Required Preparation
Lesson Timeline
Warmup  10 min 
Activity 1  15 min 
Activity 2  20 min 
Lesson Synthesis  10 min 
Cooldown  5 min 
Teacher Reflection Questions
Suggested Centers
 Can You Draw It? (1–5), Stage 7: Grade 5 Shapes (Addressing)
 Picture Books (K–5), Stage 3: Find Shapes (Addressing)
Print Formatted Materials
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Additional Resources
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