Hi everyone, welcome to my channel, I'm Gis and today we're going to study angles. Did you know that angle is widely used in our daily lives? That's it, we can use angles in the turn of a ballerina, in skateboarding maneuvers on the slope of a ramp and the landing and take-off of a plane in architecture, in civil engineering on the walls of a house.
. . you see how useful it is the angle has so if you're curious and want to learn more about angles, come with me.
. . [Music] Well guys, so to start studying angles I need you to know what an angle is, so look what I brought here for you.
you. So here I have a ray that has its origin at this vertex O so it is a ray OA, why is it a ray OA? because it originates at the vertex O and it passes through point A.
Here I have the ray OB because it starts at the vertex O and passes through point B, so when these two rays meet, what happens? they form an angle they form this region here that we call an angle so look, the definition I brought you of an angle is the region where two rays of the same origin meet, take a good look at this here they are both originating in the vertex O, so now how am I going to give a name to this angle, oh I can give it any nickname, any name? No, I'm going to look at what I have here, so I have the semi-straight line that passes through point A, it originated at vertex V, at vertex O, right, not at V and came to point B, so here I say that this angle is called AOB, the term that is in the middle the letter that is in the middle indicates that it is the vertex, so here I come and put the caret, so the angle AOB is here, the O is in the middle because it is the vertex where these two semi-straight lines meet, that's where their origins were, ok?
look here then, so I can name this O as being A, the vertex that would be the origin of these two semi straight lines, this OA, this nomenclature that I brought here for you guys with this little arrow up here means semi straight is an annotation for indicate a ray, so here I have the ray OA and the ray OB, so these two rays are the sides of the angle, very well, sides of the angle right? so here I also brought another example for you to see if you understand a little, Gis where is the angle in this second example you are seeing the angle there, right you are not seeing it explicit but it is there you are seeing two semi straight lines with the same origin, you see, right ? it originated at the vertex V and passed through point C it is the semi straight line VC so here in this region where these two semi straight lines met I have the formation of the angle so here I have the angle, I could mark it closer here I can mark it here, so wherever I mark this angle, its size will always be the same, you know why?
Because its origin is the same, right, so let's go to the names, what is the name of this angle that I drew here for you ? so the name of the angle here will be CVD and I put a caret here to indicate that that point is the vertex, okay now here so what does this V mean, this V is the vertex of the angle and VC which is the half-line VC and the ray VD they then mean the sides of the angle, very well. .
. Now let's continue a little more so with this class come here so I'll explain more to you look so we know that when I work with an angle, the unit of The measure of an angle is the degree, so for those who don't remember, when I work with angles, I work with the measurement unit degree, so if I told you, right now in your house, draw me an angle of 20, I'll say it like this then. draw an angle of 20 for me?
20 what? I have to enter the unit of measurement, so the unit of measurement is the degree and it is symbolized by this little ball here at the front, so I tell you to see an angle of 20 degrees for me, so then you already know what you have to do. draw, right, if I only put 20, what would you do?
beauty and the other thing you also need to know is that the measuring instrument to measure the angle is the protractor, you must have this here in your house, right, so this is called a protractor, so it is a measuring instrument that I use to measure angles, so let's write it here: protractor so this is going to be very important in the next classes because we're going to learn how to construct and measure angles, okay, let's continue our class then. . .
Okay guys, so now we're going to move on to the classification of angles, the classifications In fact, that's what the name that the angle receives according to its measure, so look here if I have an angle called a null angle, what does it mean to be a null angle? means that it is an angle that measures 0 degrees that is what it is when two rays, here I have a ray then and here on top of it I have another ray so this is when the two rays coincide, it is when they are one in on top of the other so there I have 0° beauty? now what is an acute angle an acute angle is an angle whose measure is greater than zero degrees so it is greater than this measure of the null angle and it will be smaller than the right angle, the angle of 90 degrees so I'm going to make one example first I want you to know what a right angle is a right angle that angle that measures exactly 90 degrees so look here with me if I draw then here your rays and here I draw this note with this little square here which indicates that I I have an angle of 90 degrees, great, but why did I say that the acute angle is greater than the null angle, which would be that, and smaller than the straight angle because look here it is a little more, it is not straight the same this one, it can be a little more inclined I can draw an acute angle like this I can draw an acute angle like this so we have a wide range of examples of acute angles since they are all those angles that are between 0 to 90 degrees cannot be 0 or 90 because if it is zero degrees it is called null and if it is 90 it is called straight then any other value that is between these two is called an acute angle, beauty?
Now let's go to our next angle which is called the obtuse angle which would be an obtuse angle so it is that angle that has a measure greater than 90 degrees that is it is greater than this right angle here, but it is smaller than 180 degrees let's see what an angle looks like an obtuse angle so come here and I'll show you so look here if I were to draw then an angle here would more or less be an acute angle if I were to draw an angle whose other half straight line was here I would have a right angle but I'm referring to the obtuse angle now, so that means I'm going to draw an angle more or less like this with a much more open region, okay, so here I have an obtuse angle it could be like this too, I have so here is a semi-straight line and here I am going to draw the other semi-straight line so look, it has an angle of almost half a turn, right, but it is not half a turn so here it is, I have an obtuse angle here, okay, so now we are going to move on to the next angles we have, two more angles, let's go? Well guys, so I brought here for you now the shallow angle, what would a shallow angle be? is an angle that measures 180 degrees exactly 180 degrees is that angle of half a turn and look here what the representation of this angle looks like then, so given the two half straight lines here we then have the angle of 180 degrees which is the angle so give half turn that you can remember then the sun setting on the horizon beauty and finally so now I brought you the angle of the entire turn the complete turn what would this angle be it is that angle that has 360 degrees that it has made a complete turn So look here if I had a semi straight line, it originated from here and it will start to turn, look what will happen it will go go go until it makes a complete turn then this semi straight here She came full circle so she has 360° beauty?
Now let's do a summary of everything we learned today, let's go. . .
Guys, I've now brought you a summary of what we studied today in the class about angles and here I have the classification of angles according to measure he has then let's go If you remember we have a null angle here, what was a null angle? is that angle that has 0 degrees and when I had a semi-straight line coinciding with another semi-straight line, then we also saw an acute angle which was that angle that was greater than zero degrees and less than 90° so here I have the angle COD right, just to remember what I called the angle, like here the O is the vertex, it goes in the middle with the caret, okay, and a really cool example of an acute angle is when you look at a plane taking off, that's right, the takeoff of the plane uses an acute angle. Now we also saw the right angle so if I look here at the angle EOF it is a right angle because it measures 90 degrees we also have an obtuse angle which is that angle that is greater than 90 degrees and it is less than 180 so here I I have an angle, it's GOH, great and an example of an obtuse angle, I brought you the clock here, look here, so if I take a clock and I mark, for example, the time and with the larger hand on 10 and the smaller hand pointing to 3 , look here that the angle formed by the clock hand, the smaller angle is the angle formed here by the clock hand, it will be an obtuse angle, I don't know if you know, but look at a clock, it has a complete turn, right?
and the clock has 360 degrees if I take into account that the hand has turned the entire clock, then we can say that here between this 12 and this 1, we then have that the hand moves 30 degrees, if I take then here between 1 and 2, it moved another 30 degrees because here it is divided into 12 equal parts and if I take 360 and divide it by 12 of 30 degrees then it means that every little bit here that the clock moves corresponds to 30 degrees, right? So if I take this obtuse angle that I formed here, it has 30 60 90 120 150 degrees, which is considered an obtuse angle, right? we also saw a shallow angle that I have angle IOJ so let's write it here so you don't forget IOJ which is considered a shallow angle because it has half a turn it is half of a full turn angle and finally we have here the complete turn angle is the one that made a complete turn and a really cool example for you to remember is that of the ballerina when she turns 360° around her body, so this is an example of a complete turn angle, right guys?
So that was our lesson today on angles. I hope you understood and satisfied your curiosity about this content and if you liked it, don't forget to subscribe here to my channel and give Gis a thumbs up, okay? Until the next class.
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