1. Distance around the outside!
"Perimeter"
"Running Laps“
Distance around the outside!

2. The perimeter of a figure is the distance around it
The perimeter of a figure is the distance around it. To find the perimeter you can add the lengths of the sides.

3. is easy with uniform shapes..
"Perimeter"
is easy with uniform shapes..
but not all shapes
are uniform...rectangle!
Like this!

4. Additional Example 1: Finding the Perimeter of a Polygon
Find the perimeter of the figure.
Add all the side lengths.
The perimeter is 17.2 in.

5. Try This: Example 1
Find the perimeter of the figure.
3.3 in.
3.3 in.
Add all the side lengths.
The perimeter is 18 in.
4.2 in.
4.2 in.
3 in.

7. Additional Example 2: Using a Formula to Find Perimeter
Find the perimeter P of the rectangle.
12 cm
3 cm
P = 2l+ 2w
Substitute 12 for l and 3 for w.
P = (2 • 12) + (2 • 3)
P =
Multiply.
P = 30
Add.
The perimeter is 30 cm.

8. How many individual boxes are there here?

9. 1 2 3 4 5 6 7

10. Learn to find the area of rectangles, triangles, and parallelograms.

11. Insert Lesson Title Here
Vocabulary
area

12. Get out your calculators!
The area of a figure is the amount of surface it covers. We measure area in square units.
Get out your calculators!

14. Additional Example 2: Estimating the Area of a Rectangle
Find the area of the figure.
A = lw
15 in.
Write the formula.
A = 15 • 9
9 in.
Substitute 15 for l.
Substitute 9 for w.
A = 135
The area is 135 in2.

15. Try This: Example 2
Find the area of the figure.
A = lw
13 in.
Write the formula.
7 in.
A = 13 • 7
Substitute 13 for l.
Substitute 7 for w.
A = 91
The area is 91 in2.

16. 3 ft.
46 ft.
A= 3 x 46 2
A= 138 ft

17. 3 ft.
46 ft.
A= 3 x 46 2
A= 138 ft

18. 5 cm.
A= 5 x 25
25 cm. 2
A=125 cm

19. You can use the formula for the area of a rectangle to write a formula for the area of a parallelogram. Imagine cutting off the triangle drawn in the parallelogram and sliding it to the right to form a rectangle.
The area of a parallelogram = bh The area of a rectangle = lw.
The base of the parallelogram is the length of the rectangle. The height of the parallelogram is the width of the rectangle.

20. Additional Example 3: Finding the Area of a Parallelogram
Find the area of the parallelogram.
A = bh
Write the formula.
Substitute 2 for b
and 1 for h. 1 2 __ 4 1
A = 2 • 1 1 2 __ 4
1 ft 4 1
2 ft
A = • 5 2 __ 4 2
Multiply.
A = or 3 25 8
___ 1 __
The area is 3 ft2. 1 8 __

21. Try This: Example 3
Find the area of the parallelogram.
A = bh
Write the formula. 1
3 ft 2
A = 1 • 3 1 2 __
Substitute 1 for b
and 3 for h. 1 2 __ 1
1 ft 2
A = • 3 2 __ 7
Multiply.
A = or 5 21 4
___ 1 __
The area is 5 ft2. 1 4 __

22. I made a DELICIOUS peanut butter and jelly sandwich for lunch today
I made a DELICIOUS peanut butter and jelly sandwich for lunch today. I’m so excited to eat it!!! Dylan came to me crying and said he forgot his lunch! Since I’m so nice, I cut my sandwich diagonally and gave one piece to Dylan and kept one for myself. Who got more of the sandwich??

23. You can make a square out of two congruent triangles.

24. If the area of a triangle is HALF the area of the rectangle, what could we use for the formula of a triangle?

25. New Formula
We can pretend the triangle is a rectangle and find the area of the rectangle! Then divide it by two.
LW ÷ 2

26. New Formula
We can pretend the triangle is a rectangle and find the area of the rectangle! Then divide it by two.
B H
1/2 BH 2

27. Additional Example 4: Finding the Area of a Triangle
Find the area of the triangle.
A = bh 1 2 __
Write the formula.
A = (9.6 • 2.9) 1 2 __
Substitute 9.6 for b. Substitute 2.9 for h.
A = (27.84) 1 2 __
Multiply.
A = 13.92
The area is cm2.

28. Try This: Example 4
Find the area of the triangle.
A = bh 1 2 __
Write the formula.
3.4 cm
A = (8.5 • 3.4) 1 2 __
Substitute 8.5 for b. Substitute 3.4 for h.
8.5 cm
A = (28.9) 1 2 __
Multiply.
A = 14.45
The area is cm2.

29. Insert Lesson Title Here
Lesson Quiz
Find the area of each figure.
3. What is the area of a parallelogram with base 16 in. and height 10 in.?
4. What is the area of a triangle with base 10 in. and height 7 in.?
4.5 m
24 ft2
41.4 m2
9.2 m
160 in2
35 in2