Students will learn how to determine the area of a rectangular pizza and a square pizza.

Students will calculate the area of a rectangular pizza and a square pizza to see which one has more area.

 

• Students will draw an array (a picture arranged in rows and columns) for a rectangular pizza and a square pizza.

• Students will construct an array using tiles to show the area of two differently shaped pizzas.

• Students will calculate the area of a rectangle and the area of a square using the formula length times width, or side times side.

  Formulas:
  L = length
  W = width
  S = sides
  A = Area
  L • W = area of a rectangle
  S² or S • S = area of a square

Mathematics
Measurement (Grades 3-4)

Benchmark A:
Select appropriate units for perimeter, area, weight, volume (capacity), time and temperature using objects of uniform size; U.S. customary units; e.g., mile, square inch, cubic inch, second, degree Fahrenheit and other units as appropriate; metric units; e.g., millimeter, kilometer, square centimeter, kilogram, cubic centimeter, degree Celsius and other units as appropriate.

Benchmark D:
Identify appropriate tools and apply counting techniques for measuring side lengths, perimeter and area of squares, rectangles and simple irregular two-dimensional shapes, volume of rectangular prisms and time and temperature.

Indicators
Use Measurement Techniques and Tools
6. Use appropriate measurement tools and techniques to construct a figure or approximate an amount of specified length, weight or volume (capacity); e.g., construct a rectangle with a length of 2-1/2 inches and width of 3 inches.

7. Make estimates for perimeter, area and volume using links, tiles, cubes and other models.

• Color tiles

• Connecting tubes

• 1-centimeter graph paper

• Paper

• Pencil

1. Have the students guess how many tiles or connecting cubes it would take to cover the surface of arrays that are 14" by 12" and 12" by 12".

2. Give the students tiles and connecting cubes to show the 14" by 12" array and the 12" by 12” array. Count how many of each it took to make the arrays with the given dimensions.

3. Explain that the students can use graph paper to show the same information. Give the children graph paper and have them draw an array representing a pizza that is 14" by 12" and 12" by 12". Then as a class, count aloud the total number of square units found in each array. Does the amount of square units equal the amount of tiles or connecting cubes used?

4. Instruct the students to color in the array that they have made and tell them that the colored surface is called the area.

5. Ask the students which pizza is larger, and why. Have them write out their response after the class discussion.

Students will be assessed on their ability to determine the area of a shape by covering it with tiles or connecting cubes and then convert that information to grid paper.

Use the included rubric to assist with evaluating the writing and mathematics.