[Music] [Applause] [Music] [Applause] [Music] okay let's do some signal geometry so this video is an introduction this is geometry if I look at the other video I want you to remember these five things that you must be thinking about before you attempt a circle geometry question five things one watch it feels do it last what does that mean okay if you are really good student do I want in the exam start from the end if you want start from the feels you know just real problem at exam but for the normal folks protip when you get the exam come maybe nine so whenever it is for you turn to the end of the paper watched you tree last questions especially the second the last question that question is going to have this equal geometry take a look at it and you want your brain to coconuts why is it universal TV / so watch it Wiz but then come and do it last listen that method really works it sets your subconscious mind on the question already and you begin to cook it up why said universe of the exam so take a look at the question who is what do you guess next thing don't use a protractor in this question so if you whip out your project anything equina measure them angles you can only wrong route already because it's not drawn the skin the diagrams and not drawn to skin so you can't use a protractor if user project you'll get the wrong answer that specifically mess up the audit draw that diagram say won't get correcting and also they expect you to use the rules so don't use a projector number three there's no major trigonometry Alice so no X Factor whip out your sign rule and cosine rule so you can put back the sine rule and the cosine rule in your pocket don't be worried about Pythagoras theorem or the trigonometric ratios sohcahtoa what they want what they are testing you on is if you can identify any rules girl geometry and figure out some angles here not really tricks that's the next part any question so number four again in three good stuff you need to know the basic rules and we're going to talk about that number five you need to know the advanced geometry so let's go into the beam second advanced the basics you must know the basic stuff like angle in a straight line is 180 all the angles in a triangle add a Tony if you don't know that come off of this video right now number two in the basics you need to know how to identify angles this is a notation that we use e BC with a little hat on Libya does mean angle at B right so that's the angle at B there notice the little hats and they be there alright I don't think I need to explain this or some people was worried about this that means angle E there's not a less than sign no greater and sign whatever that means angle so number three Basics in eternity types of channels and their properties isosceles triangle act will approach this is the basic so just making sure that you notice but I expect most of the students out there watching to know that if you don't know that as I say again and to go back and watch some sel videos man so number four quadrilaterals and their properties quadrilaterals and their properties in eternal that especially one way to say all the angles in a quadrilateral add up to 360 degrees alright so number five we're getting into the good stuff chords you need to understand what the court is a courtesan line in a meagre line here a court is a line joining two points on the circumference of a circle let's draw record 1.10 that corner can kind of skinny but I'm gonna be going okay let's do like a boat that size maybe about seven pixels six okay there you go that's a court and a Cortney divides the circle into two segments major segments and a minor segment so you have the major segment a and you have the minor segment de okay let's draw another call okay don't miss that's an ex corde that's an ex corde that's the next court day alright enough for that here's something to note about cause you see if you have a chord and you start from the center of the circle and you go towards the chord and you hit it in the middle all of a sudden this angle here 90 degrees whose rule kick that down continue the basics number 60 final thing any basics that you need to know is what is a tangent so if there's a point out here and I draw a line and it just came as past this circle like that you without going any circle I find mine cannot go any second all right so if you have a point a line I just came spasticity like that and it doesn't go inside icicle it touches the circle it means on this side of the circle that's that my friend is a tangent if you have two points if you have two lines coming out of the point it will format this circle like that two lines and if I take this line here and I join up that like that so I joined the exact point of contact so the tangent okay that was kinda bad i joined the exact points of contact for the tangent this creates an isosceles triangle so it means that this angle here and that this angle here are equal right because they are isosceles triangle that is kind of useful in the exam remember that so once again a tangent is the line just touch any circumference mm turn it he's all right so time to go into these certain theorems he said this is the advanced of these little theorems right so at the end of this video I'll just provide you one picture that you could screenshot and print out and stick on your bedroom and put a seat back on your phone and sentir friends sent a enemies Kakutani desktop wallpaper put it on your laptop wallpaper put it in your study cards so he circles their theorems let's begin with the first one the angle in a semicircle is 90 degrees how do we get a semicircle if we divide a circle by damn it sir so that's going to the center as Brittany centers of Odessa so it goes straight to the center yeah go straight to the center so if I was to make an angle like this it's gonna be 90 degrees anyway I attempt to make this that okay that's a really awful one anyway I attempt to make two straight lines from that chord you know the damn it has the longest cord right this angle here is always gonna be 90 degrees and those in a semicircle is 90 degrees but but 90 degrees okay let's look at it next one I want a simple and sweetheart next time angle ADC circumference is half the angle at the center this is the one that is most this guy's in the exam I'll show you how did this guy suggest no but okay you see this disc emote our core right I'm showing you the whole thing who is this key Motaba chord this chord AAA this was born these two angles were born out of a common core right there so what we are saying is out of this cone was born two angles one method is center here and one method is a conference today what we are seeing is the angle that is at the center is always going to be twice the angle at sadistic conference simple as that now let me show you how you can disguise this stuff [Music] right suppose I drew a next angle like this it can be harder to see this rule applying in that condition but it is still applies this angle here will still be twice this angle thing so this is how it's normally this guy's Andy Pieper all right let's move on next room and those in the same segment form a common coronae let's explain that concept so if you have a chord here and I create two lines off of that code to create a handle and I create the next angle somewhere here we are seen at those angles are equal no matter where I made it if I made one if I created one here instead it's still gonna be equal all those and those are gonna be equal I normally call this the bonnie and some people actually interlock fancy pattern some people at rental car bunnyears pattern whatever helps you remember it that's good for you so if that angle is 31 that's 31 degrees as well all right let's hustle along number 4 is about cyclic quadrilateral cyclic quadrilateral is a quadrilaterals that are trapped inside a circle so you need to notice for CXC as well well here's what you need to know you need to know that this angle and this angle which are opposite will always add up to 180 degrees the opposite angle in a cyclic quadrilateral always adds up to 180 degrees can you see the same thing happen in the green all right the angles between a radius and a tangent is 90 degrees we wrapping up here radius and a tangent so we discussed this a little bit before if I have a tangent and I run a radius from the center to the tangent that will be 90 degrees best analogy definition of a tangent and a normal the radius if students are normal so people at physics and math will understand is perfectly right this tangent here will always no matter I could attend an action if I run a radius there it's gonna meet it at 90 degrees and finally alternate segment theorem this is like probably most important theorem of all of them in terms of it can help you see a tough part any question it's probably one of the hardest one since E but you know alternate segments aramid just sangsu so good that has to be a really deep in line and really is this is the one that most of you times in half questions unlocks the final level final stage alright let's see how it works pause that rightly so if I have let's go back so you can see all this put it back if I have a tangent and I create a core from attendant notice I could have created the code anywhere cord from the tangent that's buddy cord is the red line there I create a court from this tangent this angle that he is that is made there that is created between the tangent an accord is always going to be equal to the angle and the opposite or if alternate angle in the triangle that we could create from this cone so if I create a triangle from that corn these two angles here are equal incidentally there's a next one that could be 230 be equal right here this angle is between tangents here and the core here so the opposite angle in this should be okay so whatever this angle was this angle should be equal to that as well obviously 26 right so it was 60 degrees less than 60 degrees our angle up days 60 degrees as well so this is probably the most overlooked one most important one please remember he has a complete list of all listicle term screenshot this and stick it up everywhere if you want American pick check it head to my facebook page I post a picture there so you can just download that and feel good so look out for the next video and sizzle theorems I'm going to do questions on c3 path people solution and I'll do as much as I can fit into ten minutes to just get you up so that you can get a good understanding out how to solve the question [Music]