Lesson video

Hello everybody.

My name is Mr Castle.

And welcome to today's lesson about drawing angles using a protractor.

We're looking at angle reflex angles and angles within the shape.

Now before we start, you're going to need a pen, a piece of graph paper and a protractor.

Also, please try and find somewhere quiet around your house somewhere you're not going to get disturbed and don't forget to put any sort of distractions away, perhaps put your mobile phone on silent, or move it away completely.

Pause the video and then when you're ready, let's begin.

Today's lesson is all about drawing angles with a protractor.

And we're looking at reflex angles and angles within a shape.

We're going to start by drawing reflex angles and then calculating reflex angles.

We'll then look at drawing these reflex angles within a shape at the end.

It's Quiz time.

You will need a pencil piece of graph paper and a protractor.

And you start words for today our right angle acute obtuse and reflex angle protractor, baseline crosshair vertex which is the point the angles meet.

We will be looking at the angle which is the point two lines meet the word turn, which means rotate around the point we're looking at to turn in a full 360 degrees halftones 180 degrees and a quarter turn is 90 degrees.

We'll look at acute angles which are less than 90 degrees, right angles which are exactly 90 degrees and obtuse angles which are between 90 and 180 degrees.

We'll need to know a straight line is 180 degrees and a reflex line is at between 180 and 360 degrees.

We'll look at the shapes quadrilateral Pentagon and hexagon which are four five and six sided shapes and you'll need to be able to To protractor from both sides, as well as measuring to the nearest 10th, five and one degree.

Now have a look at the shapes on screen.

And can you estimate the size of the three reflex angles in this shape, press pause.

And when you're ready, press play to continue.

Okay, so if I look at my first reflex angle is this one here, I'm going to draw myself a straight line, which I know is 180 degrees.

And then I think that might be just less than a right angle.

So I think this angle is about 260, maybe 270 degrees because my 192 degrees add on my 90 degrees is 270.

And it's a bit less than that.

When I look at my neck reflex angle, I'm looking at this one here.

Now, if I draw my line again, and I've got 180 degrees if I draw my Right Angle I've got 90 degrees.

And this time is a little bit bigger than a right angle.

So I'm going to estimate at 280 degrees.

And my final one is this one here, or Mark 180 degrees and on mark on 190 degrees, not that looks roughly about half of 90 degrees, which is 45 degrees.

So if I take 180 out of both five degrees, I think I'm looking at 225 degrees.

Okay, so I knew today is we're going to try and draw the angles using both methods.

So my first method I'm going to do 360 degrees, take away the angle.

I've got 360 take away 270 of 360 take 360 and then I've got another 30.

So I know I may draw an angle of 90 degrees there.

So I'll draw my line.

crosshairs baseline jet my crosshair check my baseline, and I'm going around to 90 degrees.

I'm drawing a 90 degree angle, which means that the remaining angle is 270 degrees.

I can do the same angle and a different way.

I'm going to use the 180 degree, add on whatever else I need to get to 270.

So I can I'm going to start with a line, it's going to be a bit longer this time.

I'm going to mark a centre point.

So cross hairs baseline and I know that's 180 degrees.

And now I need to add on or for the 180 to 200 that's 20 another 7090 so I need to add on 90 degrees.

All of that is 180 degrees.

So I'm going to turn my protractor cross hairs baseline.

I'm going to go around to 90 degrees, maybe a little bit so you can see.

90 degrees.

Okay, I know that angle there is 90 degrees.

So I know with high angle there is 270 degrees.

So done off of the use with two different methods.

Okay, my next angles I'm going to do slightly differently.

So the top one, I'm doing 315 and I'm starting with 360.

And I've got to take away 45 to give me 315 degrees, so I need to draw a 45 degree angle.

This time last time, so let's do it from this way.

10 2030 4045 I find all this is a 45 degree angle, I know this angle must be 315 degrees.

I'm going to draw my 355 degrees, I need to add on five degrees this time.

So draw my line going to measure from this side process baseline.

five degrees is there, so quite a shallow line only a small lot.

Now if I know that is five degrees, then the remainder of that must be 355 degrees.

Finally, I'm using other methods to do 225 and then 185 So, we're going to start with my straight line.

Arc, we're in the middle.

I know that's 180 degrees.

What else do I need to add to get to 225 1992 210 220 2140 and five miles so I need to I'm 45.

So this angle here, I need to measure is 45 degrees 10 2030 4045.

So idle angle is 45 degrees, which means the entire angle all the way around is 225 degrees.

And finally under 185 degrees.

I'm going to start with my straight line marker points in the centre.

I know that's 180 degrees.

So I just need to add on five degrees, zero 10.

Halfway is five.

Not very accurate.

That's all draw right again, am going to for crosshair and line out the point.

I know that's five degrees, which means our angle is 185 degrees.

So we now move into the developing learning stage of our lesson.

And your task is to draw draw a quadrilateral with angles.

210 degrees, 45 degrees 45 degrees and think, what is the remaining angle? also think what problems might there be? Pause the video, and when you're ready, press play to continue.

Okay, so I'm going to start with a courtroom.

Do you know, I don't think I need a protractor for this a great deal.

I'm going to start with my angle which is 210 degrees.

Well, if I go all the way around is 180 degrees and I need to add more 30 degrees, that's my centre point 30 degrees 10 2030.

So I know this angle here is 210 degrees.

Okay, now I'm thinking the next two lines are 45 degrees.

I'm going to cheat a little bit here.

I know that the square is corner and that's a right angle.

So I know if I match up the diagonal.

I know that's going to be 45 degrees.

Obviously, I'm just going to check it because if my printers printed out incorrectly, I might be out a little bit and look at that.

So I'm on 46 degrees swatch, then I'm going to change it, mark it off at 45 degrees.

I'm drawing again accurately.

Now, let's have a look at this.

What problems do you foresee? Just have a little pause, think about it.

Okay, so we've done two angles so far.

210 45 degrees, and then need to do another angle 45 degrees here.

I'm actually going to mark the angle a bit smaller.

This time.

We'll see why in a minute.

So I'm going to mark from this point here.

So cross hairs baseline 10 2030 4045 degrees.

Okay, that's drawn, you'll see that I have an arrowhead.

You'll also notice that because I've got a reflex angle in here, and I've got two acute angles, it means that it's not a typical shape that you'd normally see.

last task is to find out what the remaining the missile angle is at the top of a protractor cross hairs baseline 5060 not quite 60 degrees or 55 5657 degrees so it's 59 And now it's time for your independent task.

So your independent task is to draw multiple angles, have it to draw a pentagon with angles, 210 degrees, 230 degrees, 10 degrees 25 degrees.

Once you've drawn it, try drawing it again, but make the lengths different sizes.

Pause the video, and when you're ready, press play to continue.

Okay, so I've managed to draw this question lateral and I've drawn it twice my first one is bigger.

And the second one, I've changed the length of this side, the length of this side of this side and the length of this side, but this one stayed the same.

I could have changed it if I wanted to, but I don't need to Congraduations on completing your task.

If you'd like to, please ask your parent or carer to share your work on Twitter tagging at Oak national and also hashtag learn with oak.

Before we go, please complete the quiz.

So that brings us to the end of today's lessons on drawing angles with a protractor.

A really big well done for all the fantastic learning that you've achieved today.

Now before you finish up too quickly, just think back and have a look back at your notes and try and identify them.

The most important things that you learned today.

Well, I think that's about it for me, other than to say thank you very much.

Take care and enjoy your learning for the rest of the day.