Lesson video

Hi, everybody.

Welcome to your unit all about length and perimeter.

Today, we are applying all of our length and perimeter knowledge, and we're going to be answering different types of questions.

So put on your hats, tighten those ties, and tell the computer, "Now I'm a mathematician." Great, let's get started.

For today's lesson, you are going to meet the following resources, a pencil, a piece of paper, and a ruler.

Please make sure you have those in front of you.

And if not, pause the video and go and get them.

Super, let's get started.

Our first question, one side of the square measures nine centimetres.

What is the perimeter of the square? Well, we know that a square has equal sides, so all the sides would be nine centimetres and 9 + 9 + 9 + 9 is equal to 36.

Therefore the perimeter of the square is 36 centimetres.

Now it's your turn.

One side of a square measures seven centimetres.

What is the perimeter of the square? Pause the video.

Great job.

So we know, as we said before, that squares have equal sides.

Therefore, all the sides are seven centimetres and 7 + 7 + 7 + 7 is equals to 28 centimetres.

Therefore the total perimeter of the square is 28 centimetres.

Question two, what is the perimeter of the rectangle below? Now, as you can you, I've got two sides with measurements and two sides without.

But what I know about rectangles is that the sides are pairs.

So this side is the same as this side.

And this side is the same as this side.

So nine centimetres and two millimetres.

And then the other side will be nine centimetres and two millimetres.

The shorter sides are both going to be seven centimetres and one millimetre.

And I know that I need to add centimetres first.

So 9 + 9 + 7 + 7 is equal to 32, then I'm going to add the millimetres, which are equal to six.

So the answer is 32 centimetres and six millimetres.

Now it's your turn.

Here you have a rectangle.

What is the perimeter of this yellow rectangle? Pause the video.

Well done.

So we know that these sides are paired and these two sides are paired.

So we need to add our centimetres, which will be 8 + 8 + 5 + 5, which is equals to 26.

Then we need to add our millimetres, 5 + 5 + 1 + 1 is equal to 12.

Therefore, the answer is 26 centimetres and 12 millimetres.

A rectangle has the length of seven centimetres and a width of two centimetres.

The rectangle's put next to another rectangle, which has the same length and width.

What's the perimeter of the new shape.

So we know that rectangle one has a perimeter of seven centimetres and two centimetres, and we know this is seven centimetres as well.

And then we're going to add the pink rectangle, which also has the seven, the two, and the seven.

Now try and remember, we're walking around the outside.

So we need to add all of these numbers up.

Rectangle one is 7 cm + 7 cm + 2 cm, which is equal to 16.

And it's the same for rectangle two.

We need to add these two 16 centimetres up together, which is equal to 32 centimetres.

That full the total perimeter of this new shape is 32 centimetres.

And now it's your turn.

A rectangle has the length of 10 centimetres and a width of four centimetres.

The rectangle is put next to another rectangle, which has the same length and width.

What is the perimeter of the new shape.

Pause the video.

Well done.

So here we can see rectangle one is 10, 10, and four, which is giving us the perimeter of 24 centimetres.

And rectangle two is the same.

And when we add the two together, the answer is 48 centimetres.

The perimeter of the shape below is 30 centimetres.

What's the length of the missing sides? So here we can see we've been given two measurements and the total is 30.

So what we need to do is to subtract these two measurements from the total to find out the leftovers.

So 30 - 10 - 10 is leftover with 10, but we've got 10 divided by two and 10 divided by two is five.

So, the missing sides are five centimetres each.

It's your turn now.

The perimeter of the shape below is 50 centimetres.

What's the length of the missing sides? Pause the video.

So we know we need to subtract these two numbers from the whole and that is leftover with 20.

And then we need 20 divided by two, which is equal to 10 centimetres.

So the missing sides are 10 centimetres each.

Great job everyone.

Now it's time to put all of this practise into independent task.

Over the next following parts of the video are your questions.

So pause the video at each question.

Good luck! Hi everyone, welcome back.

Hopefully, that was pretty good.

So one side of a square measures six centimetres.

What's the perimeter of the square? And as you know, squares have got sides of equal lengths.

So we need to do 6 + 6 + 6 + 6, which is equal to 24 centimetres.

Therefore, the total perimeter of our square is 24 centimetres.

Check and fix.

Here is our next question.

What's the perimeter of the rectangle below? Well, we've been given two lengths and we're missing two lengths, but we know that this side is the opposite of that side.

And we know that this baseline is going to the opposite of this one.

So the missing numbers are 24 centimetres and eight centimetres, and then we need to do some adding.

24 + 24 is equal to 48.

And 8 + 8 is 16.

48 + 16 is equal to 64.

Therefore the perimeter of this rectangle is 64 centimetres.

A rectangle has a length of six centimetres and a width of three centimetres.

The rectangle's put next to another rectangle, which has the same length and width.

What's the perimeter of the new shape? So first we need to put in our measurements.

We have our six centimetres and our three centimetres, and then we need to do for our rectangle two.

Rectangle one, the perimeter is 15 centimetres and it's the same for rectangle two.

Therefore we need to add the two 15 centimetres up, which means 15 + 15 is equal to 30.

So the perimeter of the new shape is that 30 centimetres.

The perimeter of the shape below is 28 centimetres.

What's the length of the missing sides? So we know we need to subtract these two numbers from the whole.

And 28 - 10 - 10 is equal to eight, and then we need to eight centimetres divided by two, which is equal to four.

So the length of the missing sides are four centimetres each.

Great job, everybody that was so super and brilliant work today.

If you'd like to, please ask your parent or carer to share your work on Twitter tagging @OakNational and #LearnwithOak.

I really enjoyed our lesson today, and I hope to see you again soon, bye!.