1. Geometry
11.1
Areas of Rectangles

2. A = bh Area of a Rectangle
The area of a rectangle equals the product of its base and height.
A = bh 4 6
Area = (6) (4) = 24 square units

3. Perimeter of a Rectangle
The perimeter of a rectangle equals twice the length plus twice the width. 6
P = 2l + 2w 4 4 6
Perimeter = 2(6) + 2(4) = 20 units

4. Area of a Square
The area of a square is the square of the length of a side. 5
A = s² 5
Area = (5)² = 25 square units

5. P = 4s Perimeter of a Square
The perimeter of a square is four times the length of a side. 5
P = 4s 5 5
Perimeter = 4(5) = 20 units 5

6. Exercises 5. 5√3 ∙4√3 = 20 ∙3 = 60 2 ∙9√3 = 18√3 5 cm 4 ft 4 48 cm²
Let’s try #1,2,5, and 7 together. Then you try! 1. 2. 3. 4. 5. 6. 7. 8. b
12 cm
22 cm
5√3 √6 3x
y + 1 h
4 cm
9 cm
18 ft
4√3 √3
x – 1
y – 2 A
72 ft2 p
52 cm
28 cm
5 cm
4 ft 4
48 cm²
88 cm²
45 cm² 60
3√2
3x²-3x
y²–y-2
32 cm
44 ft
18√3
2√6+2√3
8x-2
4y-2
2. 2(22) + 2h = 52
2h = 8
h = 4
b = 72
b = 4
7. 3x(x -1) = 3x² - 3x
2(3x) + 2(x -1) = 8x - 2
5. 5√3 ∙4√3
= 20 ∙3 = 60
3. 2b + 2(9) = 28
2b = 10
b = 5
8. (y+1)(y-2) = y²– y -2
2 ∙9√3 = 18√3
2(y+1) + 2(y-2) = 4y-2

7. Exercises 9. Find the side of a square if its area is 64 cm². s² = 64
10. Find the perimeter of a square if its area is 144 cm².
s² = 144
s = 12
P = 4s = 48
48 cm
11. Find the area of a square if its perimeter is 40 cm.
4s = 40
s = 10
A = 10²= 100
100 cm²
12. Find the area of a rectangle if its perimeter is 30 and its base 8.
2(8) + 2h = 30
2h = 14
h = 7
A = 8 ∙7 = 56 56

8. Area Congruence Postulate
If two figures are congruent, then they have the same area.
Area Addition Postulate
The area of a region is the sum of the areas of its non-overlapping parts.

9. Consecutive sides of the figures are perpendicular
Consecutive sides of the figures are perpendicular. Find the area of each figure.
13.
14.
15.
16. 6 2 1 4 12 6 9 2 12 8 4 6

10. Exercises 6 6
13. 6 1 4
16. 2 2 4 8 4 4 2 2 72 4 32 6 1 4 16 6
Area 1: 6 x 1 = 6
Area 1: 4 x 4 = 16
Area 2: 4 x 2 = 8
Area 2: 8 x 4 = 32
Area 3: 6 x 1 = 6
Area 3: 12 x 6 = 72
Total area: = 20
Total area: = 120

11. Exercises Now you try #14. 9 x 8 = 72 2 x 3 = 6
Total area: = 78
Now you try #15.
12 x 6 = 72
12 x 12 = 144
Total area: = 216

12. Homework pg. 426 #1-31 odd use formulas for 1-16
draw diagrams for 17-31