# Lesson video

In progress...

Hi everyone, how are you today? I'm Miss Mitchell and today in maths, we're going to be comparing and sorting 2-D shapes.

In today's lesson, we'll be comparing 2-D shapes.

We'll be sorting 2-D shapes.

You will then complete an independent task.

And then a quiz.

For today's lesson, you will need a pencil and some paper.

Pause this video now to get this if you have not got it already.

What I'd like you to do, I would like you to pause the video, how many 2-D shapes can you name? How many 2-D shapes can you think of? Pause the video now.

Well done, how many did you think of? Did you think of more than four? Did you think of more than six? Fantastic.

Let's see if you can name these 2-D shapes.

So here we have a circle.

A one-sided shape.

It is a circle.

Here we have a square.

A square has four sides that are all the same length.

Here we have a one, two, three, four, five, six-sided shape and we know that a six-sided shape is called a hexagon.

Fantastic.

We have another four-sided shape and we know that a four-sided shape is called a quadrilateral.

But this is also called a rectangle.

Now, a rectangle, opposite sides are the same.

So these two sides are the same.

They're the same length.

And these two opposite sides are the same length.

So this is a rectangle but also a quadrilateral.

Over here in purple we have a one, two, three, four, five, six, seven-sided shape, which we call a heptagon.

Can you say heptagon? Fantastic.

And then in blue, we have a three-sided shape, which means it is a triangle.

But in this triangle, it looks like all the same sides are exactly the same length, which means it is a equilateral triangle.

Then we have a one, two, three, four, five, six, seven, eight-sided shape, which is called a octagon.

Octagon.

And then finally, there is a five-sided shape, which we call a pentagon.

Now, how many of these shapes did you manage to get right? Is there any that you forget? Well done.

Right, what are the names of these two shapes.

What is the same about these shapes and what is different about these shapes? Can you pause the video now to have a little think about that, please? So we have over here a pentagon.

And over here we have an octagon.

So these two shapes, they're both 2-D shapes.

What is the same about them? Well, they are both 2-D shapes.

They both have more than four sides.

They both have more than four vertices.

What is different about these shapes? They both have more than four sides but this has five sides and this shape has eight sides.

So both have a different amount of sides and vertices.

So that is what is different about them.

What did you manage to think of? And we have another two shapes.

Can you name these two shapes? What is the same about these shapes? What is different about these shapes? Can you pause the video now to have a little think? So what is the same about these two shapes? Well, this shape over here is called a rectangle.

And this shape over here is called a square.

Now, what is the same about these shapes? Well, they're both quadrilaterals.

And they're both quadrilaterals because they both have four sides and they both have four vertices.

So that is what is the same about them.

But what is different about these shapes? That's right, the length of their sides.

So in a square, all the sides are the same length.

But in a rectangle, only opposite sides are the same length.

So this side here is the same length as this side here because they're opposite.

And in a rectangle, this side here is the same length as this side here.

So that is what is different about these shapes.

Now, in today's lesson, we're going to be using a branching database to sort the shapes.

Now, a branching database uses questions to help recognise the shapes.

So this is a branching database.

Now, let's look at the first question and we always start at the top of the branching database.

The first one says does it have four sides or fewer? Does it have four sides or fewer? So now let's say yes.

One of these shapes here has four sides or fewer.

Then it says does it have exactly four edges? And we have a yes or a no.

So let's say yes.

So we're looking for a four-sided shape, or fewer, that has four edges, exactly four edges.

Now, which of these shapes here could it be? Which of these shapes here have exactly four edges? Okay, it's between two, isn't it? There's two shapes that I can see that have exactly four edges.

But then we have one more question.

Are the sides all the same length? Yes.

So we're looking for a shape that has exactly four edges.

And that all the sides are exactly the same length.

Do any of these shapes match that? Now, out of these shapes, only one of them have all their sides the same length and that is the square.

So we know that the first answer is a square and we're always going to double check.

Does a square have four sides or fewer? Yes.

Does it have exactly four edges? Yes.

Are all the sides all the same length? Yes, so you know that that is a square.

Now, when we go to this question, it was between the square and the rectangle.

So we know that this answer here are all the sides all the same length? No.

We know that is a rectangle.

But again, it's always worth double checking.

Does a rectangle have four sides or fewer? Yes.

Does it have exactly four edges? Yes, are all the sides all of the same length? No.

Yes, that fits a rectangle.

So now, we're going to go a different route down the database.

The flowchart.

So does it have four sides or fewer.

Yes, so we're still looking for a shape that has four sides or fewer.

Now, looking at these pictures, it's only between two shapes.

A triangle has four sides or fewer and the circle has four sides or fewer.

So let's keep going.

Does it have exactly four edges? No.

So again, it can still be the triangle or the circle.

Does it have straight edges? Now, between the triangle and the circle, only one of them has a straight edge or straight edges and that is the triangle.

So we know that this is going to be the triangle and again, what do we need to go and do? That's right, we need to check.

Does it have four sides or fewer? Yes.

Does a triangle have exactly four edges? No.

Does it have straight edges? Yes, it does, which means this must be the circle.

So again, let's have a check.

So let's just check with the circle.

Does a circle have four sides or fewer? Yes, because it only has one.

Does it have exactly four edges? No.

Does it have straight edges? No, it's got one round edge.

So we know that this must be the circle.

Now we go back to the top of the database.

And we go down the other side now, so we've completed all of the sides and we double checked it so we know it's all right.

So now, we're going to go down the other side.

Does it have four sides or fewer? No.

So that's the same for all of these shapes have more, have five sides or more.

Does it have six sides or fewer? Yes.

So we're looking for a shape now that has six sides or fewer.

Does it have two right angles? Now, looking at these four shapes, only one of them has two right angles.

And that is this irregular pentagon up here.

So we know that that goes there.

Let's have a double check.

Does it have four sides or fewer.

No, because it's got five sides.

Does it have six sides or fewer? Yes, because it's got five sides.

Does it have two right angles? Yes, it does down here.

So we know we've got it right.

Then we go all the way to the top of the flowchart.

Does it have four sides or fewer? No.

Does it have six sides or fewer.

Yes, so we're looking for one of these shapes that has six sides or fewer.

Now here, we've got a one, two, three, four, five, six-sided shape.

So we know that already this is going to go here but let's have a double check.

One, two, three, four, five, six, seven, so this has eight-sided shape, this is an octagon.

So this doesn't work because up here it says six sides or fewer.

So it can't be this one.

And this has seven sides.

One, two, three, four, five, six, seven.

So this is a heptagon.

It can't be this one.

So it has to be this hexagon over here.

Does it have four sides or fewer? No.

Does it have six sides or fewer? Yes, it's got six sides.

Does it have two right angles? No.

So we have now two spaces left down here and two shapes left.

So let's see.

Does it have four sides or fewer? No.

Does it have six sides or fewer? No because one has eight sides and one has seven sides.

Does it have more than seven vertices? Well, you know that this octagon has eight sides and eight vertices.

So it's got more than seven, so we know that the octagon goes here.

And then does it have more than seven vertices? No, it's got exactly seven.

Therefore that is the heptagon.

So just to recap, once you've completed one section, you always start back at the top.

So what I would like for you to do for your independent task is have a go at completing this database.

We could also call it a flowchart.

So could you pause the video, read all the questions and match it to the correct shapes.

Pause the video now and then press play when you are ready for the answers.