# The Case of the Missing Rectangle Side

Your students will become junior math detectives as they hunt down the missing side of a rectangle by applying the area formula for rectangles. The only clues they have are the rectangle's area and the measure of one side.
Need extra help for EL students? Try the Area Arrangements pre-lesson.
##### View aligned standards
Need extra help for EL students? Try the Area Arrangements pre-lesson.

#### Learning Objectives

Students will be able to find the missing side of a rectangle given the rectangle's area and measure of one side by applying the area formula.

The adjustment to the whole group lesson is a modification to differentiate for children who are English learners.

#### Introduction

(10 minutes)
• Prior to the lesson, draw a large rectangle to display.
• Tell students that today they will be on the case of the missing rectangle side.
• Inform them they will need their multiplication, division, and reasoning skills to solve the case.
• Display the large rectangle. Add to the fun by drawing a magnifying glass and tell students that they are officially on the case of the "missing rectangle side."
• Tell students that the only clues they have on the case is the area of the rectangle and the measure of one of the rectangle's sides.
• Write down the label area underneath the rectangle, defining it as the space inside the shape.
• Next, review the formula for area.
• Write down the area formula. Demonstrate an example of solving for area.

Beginning

• Allow students to discuss their ideas in partners in their home language (L1) or their new language (L2).
• Provide visuals and vocabulary cards in their L1 or L2 for the new terms.
• Give them sentence frames to help them explain the meaning of the word "area."

Intermediate

• Have them restate the meaning of the word "area" and its equation for a rectangle in their L1 or L2.
• Ask them to relay the steps you used to solve the area problem.