2. FIND THE AREA OF A RECTANGLE THROUGH MULTIPLICATION OF THE SIDE LENGTHS MATH UNIT 4 LESSON 8

3. SKIP COUNT! Use your fingers to skip count to: 7 x 6 9 x 6 6 x 6 8 x 6

4. PATTERN SHEET

5. PROBLEM OF THE DAY Danika and Lorenzo both skip-count square units to find the area of the same rectangle. Danika counts 3, 6, 9, 12, 15, 18, 21, but Lorenzo counts 7, 14, 21. Draw what the rectangle might look like. Label the side lengths and the area. The area is 21 square units. 3 7

6. RELATE SIDE LENGTHS TO AREA How many rows are in this incomplete array? And how many square units are in each row? Do we need to complete the array to find the area? Discuss with your partner how we can find the area without filling in the rest of the array. 4 7 The area is 28 square units. We can multiply the side lengths to find the area!

7. USE SIDE LENGTHS TO FIND AREA Area=?? How is this rectangle different from the others we have used? It has no gridlines, but do we still have enough information to find the area? Yes! Because we know the length and units of both sides. 6 cm 8 cm 6 x 8 = 48 Area = 48 Sq. cm Write a multiplication equation to find the area; then calculate the area. Put your hand on your head when you are done.

8. USE SIDE LENGTHS TO FIND AREA Area=?? Find the area of the rectangles as I project them. 5 cm 9 cm 5 x 9 = 45 Area = 45 Sq. cm

9. USE SIDE LENGTHS TO FIND AREA 8 in 9 in. 8 x 9 = 72 Area = 72 Sq. in

10. USE SIDE LENGTHS TO FIND AREA 10 ft 7 ft 7 x 10 = 70 Area = 70 Sq. ft

11. USE AREA & SIDE LENGTH TO FIND AN UNKNOWN SIDE LENGTH Area=27 sq cm What do you notice about this rectangle? Bingo! We know the area, but not both side lengths. Write a multiplication equation to show how to find the area of this rectangle. Use ? for the unknown side length. 3 cm ? cm 3 x ? = 27 sq cm What is the value of the ? mark? 9 cm Explain how you know. Now, write the related division equation on your board. 27 ÷ 3 = 9

12. USE AREA & SIDE LENGTH TO FIND AN UNKNOWN SIDE LENGTH Area=32 sq cm 4 cm ? cm 8 cm

13. USE AREA & SIDE LENGTH TO FIND AN UNKNOWN SIDE LENGTH Area=24 sq ft 8 ft ? ft 3 ft

14. USE AREA & SIDE LENGTH TO FIND AN UNKNOWN SIDE LENGTH Area=42 sq in ? in 7 in Wrap it up!! When you know the area and one side length of a rectangle, how can you find the other side length? Multiplication equation with a missing factor: ? X 7 = 42 Divide the area by the known side length: 42 ÷ 7 = ? 6 in

15. Problem Set!