Perimeter is the distance around the outside edge of a flat object.

l = length

w = width

Formula for Perimeter

P=l+w+l+w or

P=(2 x l) + (2 x w)

When you measure the amount of wallpaper border to go around a room, you measure it in lengths.

Would the perimeter of your bedroom or the perimeter of your house be greater?

You’re right! The perimeter of your house is greater than the perimeter of your bedroom.

Perimeter = 24 feet

Let’s find the perimeter of this surface if each square is equal to one foot.

Count the number of sides.

Count the number of sides to determine

the perimeter of this flat object.

The perimeter is equal to

12.

Try this one!

The perimeter of Family A’s pool is 12 units long.

Family B

Family A

The perimeter of Family B’s pool is 14 units long.Therefore, Family B has more side panels of the pool to clean.

Which family has more side panels of the pool to clean?

Area is the amount of surface space that a flat object has.

Area is reported in the amount of square units.

Formula for Area

A = l x w

l = lengthw = width

When you measure the amount of carpet to cover the floor of a room, you measure it in square units.

Would the area of your bedroom or the area of your house be greater?

You’re right! The area of your house is greater than the area of your bedroom.

Area = 15 square feet

Lets find the area of this surface if each square is equal to one foot.

Count the number of squares.

1 2

3

4 5 6 7 8

9 10 11 12 13 14

15

Count the number of green

squares to determine the area of

this surface. What is the

area?

The area is equal to 9 square units.

Try this one!

1

5

2

4

7

3

6

8 9

Two neighbors build swimming pools. This is what the pools look like.

Family A

Family B

Which family has the pool with the bigger swimming area?

Let’s do these problems together.

The area of Family A’s pool is?

Family A

Family B

8 square units.

7 square unitsThe area of Family B’s pool is?

Therefore, Family A has the pool with the bigger swimming area.