 Hi friends, so in the last session we discussed about the basic definition of circle what a circle was and we learned that Circle is nothing but a path which is also called locus again re-emphasizing the word locus Locust is in Greek so hence Greek word locus means path so path traced out by a point on a plane Such that its distance from a given point on the same plane is always a constant So hence you can see here again. We have taken a circle with center a and B is a point on the periphery So now first let's learn what is concentric circles all the circles having the same center are Called concentric circles if you see let me draw another circle. So this is another circle Center a and this circle is concentric to the circle C another circle We can draw so this is another circle and we can if you see there are infinitely many Infinitely many concentric circles, you can you know for a one center with different different radii We will have different different circles, right? So these are called concentric Circles beautiful isn't it so all these circles are concentric circle now We'll talk about some parts of the circle. Okay, so first is the arc. So let me draw a circle So I'm drawing this circle now B is a point. Let me take another point on the same circle Let's see now this particular curved feature BC is called the arc guys. Okay, so let me see What is this? This is nothing but the arc BC. Okay So if you see this BC is an arc, okay, similarly if you see the these two points B and C are dividing the Circle this is circle and dividing the circle into two parts One is this smaller portion BC and the other one is this larger one Okay, so hence this smaller BC curve is called minor arc. Okay What is it called minor arc and this bigger? Side curve BC is called major arc. I hope this is clear. So Let me write so it is arc a R C Okay arc. Okay. This is BC is a major arc. So we usually denote BC by we write B like that and We write C C and then we put a curve like this So this is BC and always when we write BC like this. It is assumed to be the minor arc Okay. Now if I Join these two points from B to A to C if you see this is okay, let me Gather around C A B so if you see guys, it is forty nine point zero three degrees. Let me also join the two Radio like that, okay Yeah, so now let me zoom in. Yeah, I hope you're able to see this So what I'm going to do is I'm going to just take away this here So you can see alpha is so a is the center and alpha is the angle. Can you see this angle guys? Now, let me change this point C. Let me move this point C. So You can see Let it be here. Yeah, 90 degrees. So hence if I now change B So you can see, okay B is the first point. So it's changing the circle itself Nevermind. So you can see this is 90 degree and as I move away from B the angle is increasing Isn't it's angle made by AB and AC, right? So here it is 180 degrees okay at this point and this point 180 degrees Can you see that and here it's it's like a clock, right hand moving on a clock. So here it is 270 degrees, right? So similarly you can see and it goes till 360 is one complete revolution means 360 degree, right? So you can see 358 and then it finally merges on the point B Which is 0 degrees or 0 is as good as 360 degrees and again it increases So this particular angle BAC is called the central angle, okay? Or the R for the angle subtended the word is subtended So many many times people get confused or they really don't understand what this means So hence we say angle alpha here if you see this alpha here is angle subtended the word is subtended S U, you know subtend so angle alpha is 42.97 degrees here. So angle BC Sorry arc BC subtends an angle alpha 42.97 and as alpha at point C changes the angle subtended by BC on the center Changes, can you see that this is that obtuse angle here and perfect 180 degree here and then back 270 and then 0 like that Okay, so RBC is subtending this angle. Okay, this angle BAC is called the central angle BC is minor arc and This side is the major arc. Okay, or you can say, you know, when we when we talk about we take When we write CB, so CB is anticlockwise guys. Okay, so CB If you move from C to B, what do I mean? If you move from C to B, you're moving anticlockwise, isn't it? When you are moving anticlockwise, so we write C to B in anticlockwise direction That represents minor arc and if you write B to C that means for BC in this case In this case BC means you have to move from B to C in anticlockwise direction So if you see you have to move from B to C like that, then this BC represents the major arc Usually this is the convention and hence If you write BC, it will in this case, it would be major arc But if C is like that, then this is the minor arc BC, right? And if C is like that here, so hence BC means you are going from B to C Like that in anticlockwise direction. So this in this case represents Major arc. I hope you understand. I just am repeating if you're writing from if you're writing BC like this Then you're going from B to C in Anticlockwise direction always so hence if I have to go from B to C in anticlockwise direction I will take the major path and hence in this case Writing BC represents the major arc Okay, and if I am I have to write BC as a smaller arc Then I have to write CB right in this case CB I've write first C and then from C in anticlockwise direction. I am hitting towards B. So hence CB represents Minor arc and the minor arc angle is 34.63 degree and the major arc angle will be very easily You can find out 360 minus alpha whatever the value is. I hope you understand the meaning of arc Minor arc major arc how to represent minor arc and major arc and what is the central angle?