1. Perimeter & Area
Mrs. Mitchell

2. Today’s Objectives: Learn what it means to find perimeter and area.
Practice finding or estimating the perimeter and area.

3. Perimeter Perimeter is the distance around a shape or objects.
Calculate the perimeter by counting the distance around the shape.

4. Find the Perimeter
Start Here 1 2 3 4 5 6 7
End Here 18 8 17 9 16
1 cm 15 14 13 12 11 10
Perimeter =
18cm
Let’s say one “square” is one centimeter...
Now count the squares’ sides around the rectangle...

5. Always label your answer 
Find the Perimeter
A square is the same length on each side...
4 cm
4 cm
4 cm
You can add the sides together to find the total distance around the shape!
16 cm
4 cm
Always label your answer 

6. Area Area is the number of square units needed to cover a shape.
Calculate the area by counting the squares that fill in the shape or multiplying the length times width.
Always label area as squared (ex: 1 square centimeter or 1cm2.)

7. Find the Area
6 centimeter squares
Start Here 1 2 3 4 5 6
3 centimeter squares 12 11 10 9 8 7
End Here 13 14 15 16 17 18
Let’s say one “square” is one centimeter by one centimeter or one square centimeter...
Area =
18cm2
Now count the squares in the rectangle...
You can also multiply length times width...
6 x 3 = 18 cm2

8. Always label your answer 
Find the Area
You can multiply the length times the width to find the area!
4 cm
3 cm
3 cm
4 x 3 = 12 cm2
4 cm
See – 12 cm sized squares or 12cm2
Always label your answer 

14. Today’s Ohio State Content Standards...
Grade 3 – Math
Standard: Measurement
Benchmark D: Identify appropriate tools and apply counting techniques for measuring side lengths, perimeter and area of squares, rectangles, and simple irregular two-dimensional shapes, volume of rectangular prisms, and time and temperature.
Indicator # 7: Make estimates for perimeter, area and volume using links, tiles, cubes and other models.