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Drawing angles with a protractor

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Subido el 22 de septiembre de 2013 por Samuel E.

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Excelent explanation of how to draw angles

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Let's practice drawing angles. We have to be familiar with our protractor to do this. 00:00:01
The first angle I'm asked to draw is 50 degrees. I need to start by giving myself a straight line to draw from. 00:00:10
Now that I have the straight line, I can zero my protractor using this dot on one end of the straight line that I drew. 00:00:17
And then, counting up from zero, which means this time I'm using the inner numbers on the protractor, 00:00:26
I go up to 50, and I put a line there that shows a 50 degree angle with the line that I already drew. 00:00:32
It is that easy to draw a 50 degree angle. 00:00:44
Let's try drawing a 90 degree angle, but we will use the left side of the protractor this time instead. 00:00:47
I need a straight line. 00:00:53
Once I have my straight line, I can zero the protractor on it. 00:00:54
And because I'm on the left side of the protractor, and I know I have to count up from zero, 00:00:58
this time I need to use the outer set of numbers. 00:01:02
I follow those numbers until I get to 90, and I put a dot. 00:01:05
And then I draw a line between that dot and the vertex I started from, 00:01:09
and I have created a 90 degree angle. 00:01:14
Some angles you're asked to draw are bigger than 90, though. 00:01:17
What do you do? 00:01:22
Well, start with a straight line. 00:01:23
Put your vertex of your protractor, the 0 dot, on the vertex at one end of the line. 00:01:28
And then we're counting up from 0. 00:01:37
Well, that's the inner numbers on this side of the protractor. 00:01:39
So I keep on going past 90 until I get 214, which is going to be right about here. 00:01:41
And then I draw a line between the dot that I marked and the vertex that I was using. 00:01:48
This is a 114 degree angle. 00:01:54
A 180 degree angle is also known as a straight angle. 00:01:57
If you have a line, you zero your protractor, and counting up from zero, meaning using the 00:02:02
inner numbers this time, I go all the way to 180 while it's straight over here. 00:02:12
All I'm doing when I connect them, the vertex to that dot, is I'm continuing the straight 00:02:16
line I started with. 00:02:20
So this is a straight angle, or a 180 degree angle. 00:02:22
What gets a little bit tricky is that the protractor's numbers only go to 180 and then 00:02:28
they stop. 00:02:34
But some angles you may be asked to draw are bigger than 180. 00:02:36
In order to draw this 230 degree angle, you have to know that the angle of a circle is 00:02:40
360 degrees. 00:02:52
So what we can do is we can say 360 degrees minus 230 is equal to 130. 00:02:55
Let's try drawing a 130 degree angle underneath our starting line. 00:03:03
Counting from zero, 130 is over here. 00:03:10
I put a dot, I draw a line connecting my vertex to that dot, but the 130 degree angle is this 00:03:13
smaller one here. I was asked for the 230, which is complementary to the 130. 230 is 00:03:24
what I get if I subtract 130 from the circle. So therefore, all I have to do is put this 00:03:30
symbol for the angle on the other side, and I must have a 230 degree angle. Let's try 00:03:36
the same trick with the 335 degree angle. There's my starting line. I zero my protractor 00:03:43
on it. I can't go up to 335, that's far bigger than the 180 I have in my protractor. So I 00:03:49
do the circle, 360, I subtract 335, and my answer is 25. What I'm going to do is I'm 00:03:56
going to draw a 25 degree angle instead, and then instead of putting the symbol for the 00:04:03
angle on the inside, which is a 25 degree angle I know, I put it on the outside. And 00:04:11
That must be a 335-degree angle because 25 plus 335 is equal to the 360-degree circle. 00:04:17
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Idioma/s:
en
Etiquetas:
EducaMadrid
Autor/es:
dougsimmsembedded's channel
Subido por:
Samuel E.
Licencia:
Reconocimiento - No comercial - Compartir igual
Visualizaciones:
80
Fecha:
22 de septiembre de 2013 - 10:44
Visibilidad:
Público
Centro:
IES JOAQUIN ARAUJO
Duración:
04′ 27″
Relación de aspecto:
3:2 El estándar usado en la televisión NTSC. Sólo lo usan dichas pantallas.
Resolución:
480x320 píxeles
Tamaño:
17.34 MBytes

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