Perimeter & Area

1. Perimeter & Area

2. Measurement Why do we measure objects? Name a household object that can be measured?

3. Standard Measurement Customary VS Metric inches, feet, yards VS centimeters and meters

4. NON-Standard Measurement Video example of non-standard measurement

5. Perimeter The perimeter is the distance around the outer limits of any two dimensional object.

6. Perimeter Look at the sides of an object. They come together to make a shape.

7. Perimeter If we want to know the distance around the shape, we measure the sides and add the lengths. 4” 2” 1” 5” + 3” + 3” + 1” + 2” + 4” or 18” 5” 3” 3” No matter how odd the shape is, you just add the sides together.

8. Area The area of a figure measures the size of the region enclosed by the figure. This is usually expressed in terms of some square unit. Area The area in INSIDE the figure and is expressed as square meters, square centimeters, square inches, or square feet.

9. Difference What is the difference between AREA and PERIMETER? Why do people confuse AREA and PERIMETER?

10. Misconceptions After giving definitions for perimeter and area, Mrs. Gonzalez gave her class the following problem. Find the area and perimeter for the square that has a side of 4 inches.

11. Misconceptions Gianni, a student in the class drew the square on his paper: 4” 4” 4” 4” Gianni indicated each side of the square was 4”.

12. Misconceptions Gianni wrote: Perimeter is 16 Area is 16 Is Gianni correct? Did Mrs. Gonzalez do anything wrong?

13. Misconceptions What would you say to help Gianni?

14. Misconceptions Gianni and his best friend have both worked on this problem: Given a square with side 3, find the area. 3” 3”

15. Misconceptions Gianni said the area is 9square inches and his friend Jen said it is 12 square inches. 3” Who is right, Jen or Gianni? PROVE IT! 3”

16. Misconceptions 1 2 3 4 5 6 7 8 9 How do you prove it? 3” 3”

17. Misconceptions Next, Gianni & Jen work on this problem: Find the area for this rectangle. 4” 7”

18. Misconceptions Gianni said the area is 28square inches and Jen said it is 22 square inches. 4” Who is right, Jen or Gianni? 7”

19. Misconceptions How did Gianni get his answer? How did Jen get her answer? 4” 7”

20. Misconceptions Who is right? How do you prove it? 4” 7”

21. Misconceptions What does this mean? 36 square units

22. Misconceptions Gianni looked at this problem and wrote 9 9 9 9 inches 36 square units 9 What did he do? Is he correct?

23. Misconceptions Jen looked at this problem and wrote 9 1296 inches 9 36 square units 9 9 What did she do? Is she correct?

24. Misconceptions Bart laughed at both Jen and Gianni and wrote: 9 36 ÷ 6 = 6 9 36 square units 9 9 What did he do? Is he correct?

25. Misconceptions Christy did the following: 9 6 inches 9 36 square units 9 9 What did she do? Is she correct?

26. Misconceptions If this represented a square pizza, what would be the length of the cheese stuffed crust? 9 9 36 square units 9 9

27. Vocabulary Foldable • Foldable • Two 8.5 x 11 sheets of paper • Fold (hamburger style) both sheets • Put one folded sheet on top of other (with about ¼” of bottom sheet showing • Use pencil and place a mark approximately 1” from each end

28. Vocabulary Foldable • Make sure you mare each sheet in same place • Cut sheet 1 along seem TO the line you make from each end • Cut sheet 2 between the lines

29. Vocabulary Foldable • Roll sheet 1 line a hotdog • Place in between sheet 2 • Open so slits go inside ends of center cut sheet • You now have an 4 page (8 sided book)!

30. Vocabulary • Length • Width • Height • Base • Perimeter • Area

31. Vocabulary • Polygon • Quadrilateral • Rectangle • Square • Parallelogram • Rhombus

32. Review What have you learned? Write 3 facts.