Formulas for Perimeter and Area
PERIMETER
OF A
SQUARE
P= 4s
Perimeter equals four
times the length of one
side
AREA OF A
SQUARE
A=s
2
Area of a square
equals the length of
one side squared
(times itself)
3 in.
Area of a Square
A=s²
A= 3 in. * 3 in.
A=9 sq. in.
3 in.
Perimeter of a Square
P=4s
P=4(3 in.)
P=12 in.
PERIMETER OF A
RECTANGLE
P=2l+2w
Perimeter of a
rectangle equals 2
times the length plus
2 times the width
AREA OF A
RECTANGLE
A=lw
Area of a
rectangle equals
length times
width
Perimeter of a Rectangle
P=2l+2w
P=2(3 in.) + 2 (2in.)
P=6 in. + 4 in.
P=10 in.
3 in.
2 in.
Area of a Rectangle
A=lw
A=3 in.(2 in.)
A=6sq. in.
Find the perimeter and area of each figure.
Find the perimeter and area of each figure. Show all work!
4 cm
2.5 cm
11 in.
5 in.
7 in.
4 in.
4 in.
8 in. square
Now let’s try it when the measurement needs to change.
12 in.
12
in.
There are 2 methods
2. Convert after
you have the area
We need the area
in square feet.
1. Convert first.
12”
12 in.
Convert first.
12 inches = 1 ft
Multiply 1 times 1
Area is 1 square foot.
Convert 2nd.
12”
12 times 12 = 144 square inches.
12”
How many square inches are in a
square foot?
How man inches across the top?
How many across the side?
If we draw all of the boxes
there will be 144 sq. inches in
1 square ft.
We have divide square inches by 144
to get square feet!
24
in.
18 inches
What is the
area in square
feet?
6 ft.
9 ft
Find area in
square yards.
100
cm.
250 cm.
Find area in
square
meters.
Hints:
100 cm = 1 meter
10,000 sq cm = 1 sq meter
Homework: problems below
1. Find the perimeter and area both in
feet and yards for a rectangle with a
length of 15 feet and a width of 9 feet.
2. Find the perimeter & area of a
square that has a side of 24 inches.
Give your answer in both inches and
feet.
12 in.
3. Find the perimeter and area of the 9 in.
following figure.
Don’t forget to show all work!
12 in.
6 in.