Lesson objective: Generate side lengths for possible rectangles that have a given perimeter.

This lesson provides an opportunity for students to apply their knowledge and understanding of perimeter to a real-life situation. Students are asked to create plans for an animal pen by generating dimensions of rectangles that have a perimeter of 100 meters.

Key Concept students will use:

- Perimeter is the sum of the length of the sides of a polygon.

Skills students will use:

- Adding and subtracting fluently within 100 (Grade 2, Unit 15)
- Calculating perimeter

Students engage in Mathematical Practice 8 (Look for and express repeated reasoning) as they generate side lengths of rectangles that will all have the same perimeter.

**Key vocabulary: **

- dimensions
- length
- perimeter
- rectangle
- side
- width