# Lesson video

In progress...

Hi there, my name is Miss Darwish and for today's maths lesson, we are going to be identifying missing coordinates of shapes.

But before we start, if I can just ask you to take yourself to a nice, quiet place, just so you're ready for the lesson.

Okay, so the agenda for today's session is as follows.

First of all, we're just going to recap on the four types of transformations and then we're going to be looking at missing coordinates and finding them.

Then we're going to be looking at coordinates of translated shapes and at the end of the session, there will be a quiz for you to complete.

Okay, so before we start the session, if you could just make sure that you've got a pencil out to write with, something to write on, a sheet of paper, a notebook, scrapbook and a ruler.

If you want to grab those things, then we can start.

Okay.

Hopefully you've got those things.

Let's start.

So what can you see in front of you? Tell me, can you see an x-axis? Yep, horizontal line.

Can you see a y-axis? Yep.

Can you see a grid? So what's missing? The coordinates are missing, right? Okay.

And we've got a square and it's on the, do you know which quadrant that square is in? Is it in the first, second, third or fourth quadrant? It's in the second quadrant, okay.

So now what's disappeared? The squares have disappeared, or the grid have disappeared.

So we've still got the x-axis.

We have still got the y-axis and our shape, our quadrilateral shape is still in the second quadrant but we just don't have that grid anymore.

And the coordinates are still missing off the grid.

Okay, now we don't have the coordinates on the x-axis and we don't have the y-axis either.

So we know where the x-axis is and we know where the y-axis is.

We just don't have the coordinates, it's not labelled.

But what we do have is one of the vertices of our quadrilateral shape, we do know the coordinates.

What are they? Read them out to me.

7,3, so it has an X coordinate of -7, well done and a Y coordinate of 3.

Okay.

That makes sense, because we're in the second quadrant, which means the X is negative and the Y is positive.

Good, right, now we're going to try and figure things out.

Because we know that the coordinates of one of the vertices is -7,3 if we go down, it has an X of 7 and that's where 7 goes.

Can you see that? And then what would I label across the y-axis? 3, well done, because we know -7,3.

Okay, easy enough? Now we've got another one of the coordinates on the square.

What do we know about it? So it's marked in like a bluey green, let's call that a seagreen colour.

What do we know about that coordinate? Do we know the X? Do we know the Y? Do we know both? Do we know one? We definitely know the X coordinate.

And what's the X coordinate? Seven.

So even though our x-axis and our y-axis are not marked, just by knowing the coordinates of one of the other vertices, we can actually work out the coordinates of another one.

So we definitely know that it has an X of 7 because the one on top had an X of 7 and it's on the same x-axis.

Can you see that? Okay.

What about the one marked in orange? What do we know about it? Do we know the X? Not quite sure yet.

What about the Y? it has a Y of 3 and how do we know? Again, because the coordinate next to it has a Y of 3 and it's on the same line, it's on the same y-axis.

Well done if you said that.

Okay, now we're going to have a look at missing coordinates.

So we have the x-axis, we have the y-axis and we have a square or a quadrilateral shape with the vertices A, B, C, and D.

Can you see that? Okay.

Now we've got the coordinates of two of the vertices, which two vertices do we know the coordinates of? A and D, well done.

We don't know B and C but we're going to see if we can work them out.

Are you ready for this? This is a challenge.

I love a challenge.

So let's see if we can work them out.

First of all, what do we know about A? What are the coordinates of A? It has an X of 10 ,good and a Y coordinate of 5, well done.

And what do we know about D? It has an X of 14, good and a Y of one.

Okay.

And that should help us work out B and C.

If you would like to just pause and just jot some notes down about what you might think the X or the Y for B or C are, then go for it.

Otherwise, we'll work through this example together, don't worry.

So it's up to you.

Okay.

So just by looking at point A, okay I know, point A 10,5.

these are the coordinates for A.

It has an X of 10.

Because I know that, straight away, I'm going to mark it on my x-axis.

Can you see that? What does that mean C has an x-axis of? what does that mean, sorry, C has an X coordinate of? Same as A, can you see why? Okay.

There we go.

C has an X coordinate of 10.

Because we knew about A, we know the X and Y of A, we're just going to plot what we know onto that graph, okay? So we've got the x-axis.

We know where 10 is on that x-axis.

So that means A and C have an X coordinate of 10.

Okay.

And then A has a Y of 5.

Can you see that? A has a Y of 5.

What does that mean then? What else has a Y of 5? What else? A, B, C or D has a Y coordinate of 5? B, well done.

Can you see why? Okay.

Well done.

Okay.

We've still got something missing.

We've still got a coordinate for B and C missing.

Let's have a look.

So we went through A, we knew the coordinates for A, 10,5 and we labelled them.

Now, guess what we're going to do? We're going to have a look at D.

D has an X of 14, so we're going to mark that on our x-axis, so we know where 14 is.

and it has a Y coordinate of one.

So, because D has an X coordinate a 14, what else has an X of 14? B has the same X coordinate as D.

can you see that on there? So we put that in.

So now we know B 14,5.

and there we're still going to carry on.

So D we marked the X coordinate for it but we didn't mark the Y coordinate, so what are we going to mark on there? One.

I'm going to give you time just to read that and have a look at that, see if that makes sense.

So A has the coordinates 10,5.

C has the same X coordinate as A, 10,1.

and D has the same Y coordinate as C, 14,1.

And then B will have the same X coordinate as D, 14,5.

Okay.

Hopefully that wasn't too tricky.

So, let's have a look at this, true or false.

Are you ready? We've got a triangle with three vertices, obviously.

A, B and C.

So if I know the coordinates for points A and C, then I can find the coordinates for B.

Do you think that's true or false? I'll read it once more.

If I know the coordinates for points A and C, then I can find the coordinates for B.

Is that true, or is it false? What do you think? I'll give you 10 seconds and then do this for true or this for false.

You ready? Have a think first, thinking time.

Okay and five, four, three, two, one.

What do you think? let's have a look.

if I know the coordinates for point A, what will A and B have the same, the X or the Y? A and B will have the same X.

They'll have the same X, won't they? And what about B and C, will they have something similar? They'll have the same Y.

So if I know the coordinates for point C, then I know the X and Y marked.

Okay, B will have the same X coordinate as A and it will have the same Y coordinate as C, So it is true.

Well done if you had your thumbs up and you said true.

So actually, we only needed the coordinates A and C to actually be able to find out B.

See how easy missing coordinates are? We don't actually need the X or the Y to be labelled.

Okay.

Let's have another go, true or false again.

So if you think true, if you think false.

if I know the coordinates for points B and C, then I can find the coordinates for A.

So this time B and C we know, A we don't know.

But can I find out A if I know B and C? Have a think first.

So if I know the coordinates for B and C, then I'll know the coordinate for A.

Okay, I hope you had your thinking time.

We're going to give you 10 seconds now, true or false? And five, four, three, two, one, true or false? What do you think? Let's have a look.

If I know the coordinates for point B, then I know the X and Y marked and I've marked them there.

And if I name the coordinates for point C, then I know the X and Y that are marked.

So do I know the X for A? Definitely.

I can see it on the X, on the pink line.

Do I know the Y for A? So that was false, so well done if you did this.

Even though we had the coordinates for B and C, they didn't help us when it came to knowing the Y coordinate for A.

So we definitely know the X coordinate for point A but not the Y.

Okay, well done.

I know missing quarters is always my favourite thing, so hopefully you found that like a nice challenge.

So now it's time for you to pause the video and have a go at the questions yourself.

Once you've checked through, bring something to mark with.

If you want to bring a red pen and then we'll go through the answers together.

Good luck.

Okay.

How was that? Let's go through the answers together and have a look.

So the question that I left you with was, again, an x and a y-axis and we didn't have any of the markings on the X and the Y.

And it said, find the missing coordinates.

And we had the coordinates for D and we had some of A and some of C.

So we've got a quadrilateral shape and it is in the third quadrant, where both X and Y are negative, okay? So that's something that you could then, after you've completed it, check.

Are my X coordinates and my Y coordinates both negative? Because I know my shape is in the third quadrant where both X and Y are negative.

So do you want to check that through now? Are all your X's and Y's negative? If they are then good stuff.

Let's go through the question then.

Okay.

So what do we know about A? We know it has an X of -8, we don't know the Y.

B we don't know anything about.

C, we don't know what the X is but we know it has a Y of -2.

And then D we know the most about.

We know the X is -3 and the Y is -4.

So based on the information that we know and we have, we can put these markings on, hopefully that you've got the same markings as well.

So on the x-axis, we know where point -3 is and we know where -8 is.

And on the Y, we know where -2 is and we know where -4 is.

So A is -8,-2.

B -8,-4.

C minus -3,-2.

And then D was the one we knew anyway, -3,-4.

So just check those through.

Okay, well done if you've got those right.

So if you would like to share your work with Oak National, then please ask your parent or your carer to share your work for you onto Twitter, tagging @OakNational and use the hashtag #LearnwithOak.

I would love to see the work that you did today.

Now I'm going to leave you to go and complete the quiz.

But before I do, I just want to say a massive well done on all the learning that you have done today.

I know that wasn't one of the easiest lessons and actually I love a challenge of coordinates and hopefully you did as well.

So now it's time for you to complete the quiz.

So I will leave you to do that.

And I will just say good luck with it.