Students will investigate the concept of area of rectangular figures by tiling the figures using “unit squares" and comparing the areas to the multiplication of the lengths and widths of the figures.

- slide 1 of 18
Without overlapping or leaving gaps, cover the rectangular figures with “unit squares". To determine the areas of geometric figures, count the number of “unit squares" used to cover the figures. Record the lengths and widths of the rectangular figures, multiply the lengths and the widths, compare the products to the areas.

**Lesson Objective:**The lesson is aligned to the Common Core State Standards for Mathematics – 3.MD.7a Geometric Measurement – Relate area to the operations of multiplication.**Materials Required:**unit square, graph paper, calculator - slide 3 of 18
3. Count the number of “tiles" shaded in Figure A.

4. How many “tiles" are shaded in Figure A?

5. What is the area, in square units, of Figure A?

6. What is the unit length of Figure A?

7. What is the unit width of Figure A?

8. Multiply the length times the width of Figure A.

9. Compare the number of tiles used to cover Figure A to the product of the length and width of Figure A.

10. Write a statement describing the comparison.

- slide 4 of 18
11. Count the number of “tiles" shaded in Figure B.

12. How many “tiles" are shaded in Figure B?

13. What is the area, in square units, of Figure B?

14. What is the unit length of Figure B?

15. What is the unit width of Figure B?

16. Multiply the length times the width of Figure B.

17. Compare the number of tiles used to cover Figure B to the product of the length and width of Figure B.

18. Write a statement describing the comparison.

- slide 5 of 18
### Answers:

4. 63

5. 63 square units

6. 9 units

7. 7 units

10. The number of tiles used to cover Figure A is 63. The product of the length, 9, and the width, 7, is 63. The number of tiles used to cover Figure A is the same as the product of the length and the width of Figure A. The area of Figure A is 63 square units.

12. 48

13. 48 square units

14. 8 units

15. 6 units

18. The number of tiles used to cover Figure B is 48. The product of the length, 8, and the width, 6, is 48. The number of tiles used to cover Figure B is the same as the product of the length and the width of Figure B. The area of Figure B is 48 square units.

- slide 6 of 18
### Individual or Group Work:

1. Record the number of tiles shaded in Figures C, D, E, and F.

2. Record the area, in square units, of Figures C, D, E, and F.

3. Record the lengths and the widths of Figures C, D, E, and F.

4. Record the products of the lengths and the widths of Figures C, D, E, and F.

- slide 13 of 18
### Answers:

4. 25

5. 25 square centimeters

7. 18

8. 18 square centimeters

10. 20

11. 20 square centimeters

13. 22

14. 22 square centimeters

18. 16

19. 16 square centimeters

- slide 14 of 18
- slide 17 of 18
### Answers:

3. 8, 22, 15

4. 8 square meters, 22 square meters, 15 square meters

7. 36, 8, 18

8. 36 square inches, 8 square inches, 18 square inches

11. 24, 15, 27

12. 24 square feet, 15 square feet, 27 square feet - slide 18 of 18
### Download a Copy of the Lesson

**Finding the Area of Rectangular Figures Using Multiplication**

#### Grade 3 Math Lessons on Geometric Measurement

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