1/12/20

We are going to move on for the rest of the week but will come back to time later in the year. for the rest of the week we are going to look at perimeter and area of a shape. 

We will start by looking at perimeter. Perimeter is the distance around the edge of a shape. For today we will keep it simple and work with squares and rectangles. 

To work out the perimeter you add all sides of the shape together. Make sure to check the unit of measure.

Lets look at a couple together.

If the shape is a square you will only be given the length of 1 side, like the image below.

A square has 4 sides of equal length. So if 1 side is 5 cm that means that all 4 sides are 5 cm. So to work out the answer for the perimeter of a square we can use 2 different methods 

Lets look at both methods

Method 1

Add all sides together.

5 cm + 5 cm + 5 cm + 5 cm = 20 cm

Method 2

Multiply the length by the number of sides there are.

5 cm x 4 = 20 cm

Lets have a go together at the following square

Method 1

15 cm + 15 cm + 15 cm + 15 cm = 60 cm

Method 2

15 cm x 4 = 60 cm

Now lets look at a rectangle.

First lets look at the following image and discuss what you notice.

The think that you should have noticed is that the opposite side of the rectangle are the same.

So lets look at how to work out the perimeter of the rectangle. Just like the square there are 2 different methods.

Method 1

Add all sides together.

4 m + 7 m + 4 m + 7 m = 22 m

Method 2

Multiply the length  of each side by 2 then add them together.

7 m x 2 = 14 m

4 m x 2= 8 m

14 m + 8 m = 22 m

Lets have a go together at the following rectangle.

Method 1

3 m + 12 m + 3 m + 12 m = 30 m

Method 2

12 m x 2 = 24 m

3 m x 2= 6 m

24 m + 6 m = 30 m

Your turn. 

Look at the images below and work out the perimeter of the squares and rectangles.

Home learners please could you take a photo of your answered questions and email it to Mr Hindman on Purple Mash.