Lesson video

Hello, and welcome to today's lesson about bearings and angle facts.

For today's lesson, all you'll need is a pen and paper or something to write on and with.

If you could take a moment to clear away any distractions, including turning off any notifications.

And finally, if you can find a quiet space to work where you won't be disturbed, that would be brilliant.

Okay? When you're ready, let's begin.

Okay, so the try this task.

Just before you start this task, I'd just like you to remember what's important about equilateral triangles, okay? Something important about equilateral triangles to do with the angles, that's really useful for this task.

So have a go, pause and have a go in three, two, one.

Okay, welcome back.

Now, hopefully you remembered that the important property of an equilateral triangle is that the angles are at 60 degrees All of the interior angles, not the exterior angles.

So this here is 60 degrees.

Now this here is 60 degrees, but what if I split this? Like so into two triangles that will make a right angle there and because it's the midpoint.

So this angle at the top, it's been cut in half.

So it's now 30 degrees.

Now this will help us find the bearing of b from a.

So I'm going to draw a North line in, I'm going to go clockwise until I hit that line.

Okay so what angle is that? Well, it's 30 degrees, less than a full turn.

It's 30 there.

So that is 150 degrees, okay? So find the bearing of b from a that is a bearing of 150 degrees.

What else could you have worked out? Or you might have worked out this one.

That is 270.

And what about this one? Hmm, well, if that's North, we've got a right angle there.

So that means that, that is 30 degrees, okay? So the bearing of a from c is 030 and that one is 270.

Okay so now we're go to apply some angle facts into some bearings problems. Now, find the bearing of b from a.

So we are at a, so that's that's good, we've got our North line from a.

Does that angle start from North? Yes.

Does it go around clockwise? Yes.

Is it three figures? Yes.

Well then that is just our bearing and that's our answer.

Your turn, have a go, pause the video in three, two, one.

Okay, so hopefully you've had a go and hopefully you saw that was just 201.

You may not even need it to pause the video, you may have seen that already.

Okay, slightly trickier now.

Okay, this bearing, does it start from North? No it does not start from North.

So the bearing is not 017 degrees.

Well, if we're starting from North, we want this angle there and you might be able to tell that, that is a right angle.

So, that means that our bearing is going to be 107 degrees.

Your turn, I'd like you to pause the video and have a go.

Okay? So hopefully you've had a go and hopefully you've seen that this here is up to that dotted line is 180.

And then the bearing of that line is 17 more.

So we've got 118 plus 17, which gives us a bearing of 197.

Okay? So really well done if you've got that.

All right, next one.

So we starting off, we need to go clockwise.

So we want that angle there, we need to work out that angle.

Well, that angle is 17 less, than a half turn.

So, 180 take 17, which gives us 163.

So our bearing is 163.

Okay your turn, pause the video if you need to pause in three, two, one.

So hopefully you've managed to do that, hopefully you've notice that, that is 90 degrees.

So then that line there is 17 less than 90 degrees.

So, we should have a bearing of 073.

Okay next one.

Find the bearing of b from a.

So we're at a, alright? And that's going, 17 that way.

Oh, that's anti-clockwise we don't want anti-clockwise, we want clockwise, so we want this angle here.

Hmm.

Well that is 17 less than a full turn.

So 360 is our full turn take away 17 and we should get 343, so that is our bearing.

Okay, next one, you turn.

Pause the video and have a go, pause in three, two, one.

Okay so hopefully you've had to go, and hopefully you did this calculation, 360 minus 140 and you got the answer of 220.

Okay.

So if you found that, quite straightforward, that's absolutely brilliant.

If you struggled a little bit, then that's okay, we're going to do some practise now.

So I would like you to pause the video to complete your task.

Resume once you've finished.

Okay and here are my answers.

So pause the video and mark your work.

Okay so now we've got the explore task.

Yasmin describes a journey around an equilateral triangle.

Describe a similar journey around an equilateral hexagon and octagon.

Okay so this has six sides, so that is the hexagon.

This has eight sides, so that is the octagon, okay? And this triangle there is the same in all the pictures.

So that one's five, that's five, that's five, that's five.

All of these are five.

Okay? And remember what we said about angles in an equilateral triangle, that's really important.

So I'd like to pause the video and have a go and come back when you're finished.

Okay, so here are my answers.

I'd like you to pause the video and mark your work.

And for the next question, pause the video and mark your work.

And that is it for today's lesson.

Okay so really well done.

Thank you very much for taking part and well done for working hard.

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

I look forward to seeing you in the next lesson, thank you.