Area and Perimeter Teaching Suggestions:

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1 Area and Perimeter Teaching Suggestions: Use math definition posters to discuss: dimension, two-dimensional shapes, length, width, perimeter and area. Brainstorm examples of each, and develop vocabulary concepts. Area: Introductory Activities 1. Ask students why people need to know the area of objects. Brainstorm as a whole group and accept all reasonable answers. Examples: Amount of paint to buy to cover a wall, amount of carpeting, floor tiles, etc. 2. Create brightly-colored poster board models of a square inch, a square foot and a square yard for each group of 3-4 students. Ask students to decide which unit they would use to calculate the area of different rectangular or square shapes in the room. Examples: desktop, ceiling, floor, book, pencil box top, etc. Ask students to explain their reasoning. 3. Give student pairs or groups 4-8 sheets of inch grid graph paper. Ask students as pairs (or groups) to estimate the number of square inches that would cover their desktops, their math books, and other smaller rectangular or square shapes in the room. Ask them to record their estimates in their math journals, and then use the inch grid graph paper as a non-standard measure to calculate the area of the objects they chose. (Do several examples as a whole group before asking students to complete this activity independently.) 4. Measure the dimensions of the classroom. As a whole group, calculate how many 1 foot square floor tiles would be needed to tile the floor. Decide how many square feet or square yards of carpeting they would need to recarpet the floor of the classroom.

2 Perimeter and Area Perimeter is the measurement of the distance around the outside of a figure, or shape. We measure the length of all of the figure s sides and add them together to find the perimeter. This is a map of Sarah s garden. Each square = 1 foot long. What is the perimeter of Sarah s garden? Find the perimeter of Sarah s garden by adding the lengths of all of its sides. Area is the measurement of the inside of a shape, or figure. It is measured in square units. One square inside of Sarah s garden = 1 square unit. In this map, each square equals 1 square foot. What is the area of Sarah s garden? Count the squares inside to find out. Billy had a garden, too. He wanted to put a fence around his garden. Billy measured the perimeter of his garden. What is the perimeter of Billy s garden (the length of each square is 1 foot)? If each square = 1 square foot, what is the area of Billy s garden if each square = 1 square foot? Count the square units inside of Billy s garden to find out.

3 Perimeter Perimeter is the measurement of the distance around the outside of a figure, or shape. We measure the length of all of the figure s sides and add them together. Rectangles have two pairs of equal sides. The equal sides are on opposite sides of the rectangle. Find the perimeter of the two rectangles below: Perimeter = feet Perimeter = feet Rectangles have two pairs of equal sides. The equal sides are on opposite sides of the rectangle. Because we know this, we can find the perimeter of a rectangle if we know the measurement of one side of its length and one side of its width. The opposite sides have the same measure as the ones we already know. First, write the measurement of each opposite side that is not labeled on the rectangles below. Next, find the perimeter of the rectangles using this information. 12 feet 5 feet 4 feet 8 feet

4 Perimeter Practice Directions. You will need a ruler and a partner. As partners, find 10 different rectangular or square shapes in the classroom. Measure the length and width of each. Record the measurements in the chart provided. When you are done, calculate the perimeter of each object you chose. Some objects that you choose to measure won t have sides that are an exact number of inches. Look at the example to the left. Its length is 11 and ¾ inches. Its width is 8 and ½ inches. When this happens, round up or down to the nearest whole inch. For example, the length of this rectangle would round up to 12 inches, and its width would round up to 9 inches. Fill out the chart below to show your work! Object Length Width Calculation of Perimeter book 11 ¾ inches 8 ½ inches = 42 inches

5 Area Area can be calculated by counting the number of square units on a grid that are inside of a figure or shape. Another way to calculate area is multiply the length of a figure by its width. Length Width If you know your multiplication facts, you can multiply 5 X 4 = 20. If you don t know how to multiply yet, you can use skip counting or repeated adding. For example, in the figure above, there are four rows of 5 units each. You could add = 20; or you could skip count each row by fives: 5, 10, 15, 20. Directions: Skip count by rows, add rows, or multiply length by width to calculate the area of the figures below: The area of the rectangle to the right is square units. The area of the rectangle above is square units.

6 Area Practice Directions: Add by rows, skip count by rows, or multiply length by width to calculate the area of the figures below: Area = square units Area = square units Area = square units Area = square units

7 More About Area Area is the measurement of the inside of a figure. It is measured in square units. A square unit can be very small, such as a square inch, or it can be very large, such as a square mile. The unit that we use to cover the area of a figure depends upon how big the figure is. For example, we would use square inches to calculate, or figure out, the number of square units that cover our desktops. We would use square feet or square yards to calculate the square units that would cover the floor or ceiling of our room, our house, or our backyard. We would use square miles to calculate the number of square units that would cover our city. This is a picture of Eddy s garden. He used square feet to calculate the number of square units that would cover his garden. The area of Eddy s garden is square feet. Directions: Decide whether to use square inches, square feet, or square miles to calculate the area of each figure listed below: 1. a piece of notebook paper: 2. a swimming pool: 3. a state: 4. the floor of your living room: 5. a continent: 6. your teacher s desktop: 7. a city: 8. a country: 9. a book: 10. The top of a laptop computer:

8 Answer Keys for Area and Perimeter Worksheets: Page 1: Sarah s garden: Perimeter = = 20 feet Area = 5 X 5 or 25 square feet Billy s garden: Perimeter = = 22 feet Area = 7 X 4 = 28 square feet Page 2: Perimeter feet feet feet feet Page 3: Perimeter Practice Answers will vary Page 4: Area Rectangle above: 7 x 3 = 21 Rectangle to the right: 2 x 8 = 16 Page 5: Area Practice square units square units square units square units Page 6: More About Area 1. square inches 2. square feet 3. square miles 4. square feet 5. square miles 6. square inches 7. square miles 8. square miles 9. square inches 10. square inches