Lesson 4 Area of Rectangles

    • Let’s find the area of more rectangles. 

Warm-up Which One Doesn’t Belong: Area and Arrays

Which one doesn’t belong?

  1. A rectangle partitioned into same size squares.
  2. A rectangle with 24 same size squares and a dot inside each.
  3. Array. 4 rows of 5 dots.
  4. 5 groups of 4.

Activity 1 What Did I Create?

Can you and your partner draw the same rectangle without looking at each other’s drawing?

    • Partner A: Draw a rectangle on one of the grids provided. Describe it to your partner without telling them the total number of squares.

    • Partner B: Draw the rectangle your partner describes to you.

    A blank graph.
    12 unit by 12 unit square grid.

  2. Place your two rectangles next to each other. Discuss: What is the same? What is different?

  3. Switch roles and repeat.

Activity 2 Find the Area

Find the area of each rectangle and include the units. Explain or show your reasoning.

  1. Diagram. Rectangle partitioned into 2 rows of 9 of the same size squares.
  2. Diagram. Rectangle partitioned into 6 rows of 5 of the same size squares.
  3. A rectangle partitioned into same size squares.
  4. Diagram. Rectangle partitioned into 5 rows of 9 of the same size squares.

Practice Problem

Problem 1

Find the area of the rectangle. Explain or show your reasoning.

Diagram. Rectangle partitioned into 5 rows of 8 of the same size squares.