SECTION 11.1
AREAS of
RECTANGLES
and SQUARES
WARM UP
1) Find the area and perimeter of a square
A = 5 ·+55=+25
5 + 5 = 20
that is 5 inches long. P
2) The area of a square is 64 cm2. What is
the perimeter?
A
P = 64,
8 + 8 +8 8= +side
8 = 32 cm
3) The perimeter of a square is 28 inches.
What is the area? A
P=7
28,
· 7 = 28/4
49 in2= 7
PERIMETER
• TO FIND PERIMETERS
• Add all the side lengths
together!
Area of SQUARES
• Area of a square = sides2 = s2
2
7
3
2
A 
3
2
2
4
2
  
9
3
2
3
Area of RECTANGLES
• A = bh
or
A = lw
• Base x height
length x width
2
7
3

A4 2 3
A8 3

4
2
3
Find the area and perimeter.
A  bh

A 4 5
4
5
 6 2 
A  46 5  2
A  24 10



P  2l  2 w  2 4 5  2 6 2
P  8 5  12 2
6
2
Remember you can only
combine “like” radicals!
NOTE: It is a rectangle.

Give the expression for the
area and perimeter.
A = 2x(x – 3)
A = 2x2 – 6x
That is as far
as you can go!
x- 3
P = 2(x – 3) + 2(2x)
P = 2x – 6 + 4x
P = 6x – 6
2x
NOTE: It is a rectangle.
Find the area and perimeter.
HINT: It’s a special right
triangle! I love these guys!

300
5 3
A5 5 3
10

A  25 3

P  2(5)  2 5 3
60 
5
P  10  10 3

SAT Problem
• The area of the rectangle is 60 square units.
Find the value of x.
½x
2x - 1
a) ⅔
b) 7
c) 8x = 8
d) 40
e) 59
A = bh
60 = (2x – 1)(½x)
60 = x2 – ½x
0 = x2 – ½x – 60
This is UGLY. 0
Try
= to
x2 Guess
– ½x –and
60 Test.
Real Life Applications
• How much will it cost to blacktop the
driveway shown if blacktopping costs
$11.00 per square meter?
HINT: ADD A LINE!!!!
HINT: You are finding area!
A = 5(6) = 30 5 m
12 m
4m
TOTAL AREA =
72 + 30 = 102 m2
6m
A = 4(18) = 72
TOTAL COST =
102(11) =18$1,122
m
9m
4m
Draw a picture
• A path 2 m wide surrounds a rectangular
garden 20 m long and 12 m wide. Find the
384 –Area
240 =- Garden
144 m2
area of the PATH. Total
A = 24(16) = 384 m2
2m
A = 20(12) = 240 m2
2m
12 m
16 m
2m
20 m
2m
24 m
PRACTICE
• Page 426
• #2 – 12 EVENS
• #23, 24
Area Video
• Don’t you just love these videos!!!!