The purpose of this activity is for students to measure the side lengths of a rectangle and multiply them to find the area. Students may use the ruler to create tick marks along the sides of the rectangle to help them visualize square units or multiply the side lengths. Either strategy is fine as students work toward finding the areas of rectangles with labeled side lengths.

• “¿Cómo les ayuda medir con una regla a encontrar el área?” // “How does measuring with a ruler help you find the area?” (Measuring with the ruler gives the side lengths, which we can multiply.)

The purpose of this activity is for students to create a rectangle with a given area. Students use what they know about area and the structure of rectangles to decide on the side lengths of the rectangle. Students use tape (painter's or masking) to create the rectangles. They should have enough tape to create square feet within the rectangle, but should be encouraged to mark the 1 foot intervals to help them visualize the square feet inside the rectangle, if needed.

In the Activity Synthesis, each group shares strategies for creating a rectangle and how they know the area is the given number of square feet.

When students think about the structure of a rectangle and use it to create a rectangle with a given area they are looking for and making use of structure (MP7).

• Select each group to share the rectangle they created and how they know it has the given area.
• Consider asking:
  • “¿Hay otras longitudes de lado que nos den un rectángulo con un área de ___  pies cuadrados?” // “Are there any other side lengths that would give us a rectangle with an area of ___ square feet?”
  • “¿Cómo sabemos que este rectángulo tiene un área de ___ pies cuadrados?” // “How do we know this rectangle has an area of ___ square feet?”