As a mechanical engineer myself there's no trick and its grade 6 math. The amount of math you take you don't even stop for 5 seconds to think of a problem like this.
If you look at the triangle inside a circle where the hypp = radius And you know that youre looking for x aka the adjacent you know its cosine. And the length of it will be cos(theta)*radius Therefor 15*cos(72°) ... Just by a glance you can get all the sides. |\ | \ cot x c|___ \ s| /| \ c| / | \ tan x |/x°_|____\ sec x Inner triangle ( hyppotenuse represents radius) / | / | Radi / | sin x / | /_X°____| cos x
i understood it a little but, tbh the reason im so bad at math is because right when im beginning to understand and it clicks for me the teachers go to fast and i get confused
In there exam papers, they have multiple choice questions AND they’re easy ass questions like this one 🤯 They complain about how hard school is when they’re the luckiest
It's a trick question! The answer should be "None of the above", b/c when an angle doesn't have the degree-symbol (the little circle at the upper-right corner), it means that the angle is IN RADIANS (or a pure number, with no units/dimensions). So NONE of the choices is correct. The correct answer is 15 cos(72 deg) which is not the same as 15 cos(72) = 15 cos(72 rad). [Sorry, I couldn't resist... LOL! ;-)]
@@ensign4740 the sine rule isn't needed for right angle triangles. If they were referring to sine itself yeah it can be used, but probably shouldn't for simplicity sake
@@ensign4740 180-72 = 108 108-90 = 18 (The side opposite angle 90) X I forgot what the number is ----- = ------ Sin(18 Sin(90) Then just make X the subject then yeah…
You can literally every question is swap the denominator [only if one has a number and top doesn’t] bring the denominator forward and put it in front of the sign and your done
I got it in a second and I’m in 7th grade, the only trick is to just remember the equations eg in this question adjacent= cos of angle times hypotenuse
Hey loved the vid, Chat I have an odd question, can someone give me a random middle school, 8th grade math problem? For my niece but we made a bet, if someone from chat sends her a Math problem and if she gets it right I have to buy her all the cookies and cream ice cream that'll fit in the deep freeze and it's only half full. If she gets it wrong then she gets to help me clean my Ninja ZX6-R and Yamaha YZ 250 GYTR. And I mean deep clean and refine to pristine shape. I ain't maintained them in over 2 months 😅😅😅 If your still reading you have my respect. ✌️ Y'all
Bro I didn't look at the options and found the solved to find the value of cos 72.... I first use the fact that cos 72 = sin 18 by trigonometry of allied angles. And then, if we consider A = 18, 2A = 90 - 3A 》2sinAcosA = cos3A = 4cos^3A - 3 cosA Knowing that cos^2A = 1 - sin^2A, we get 2sinA = 1 - 4sin^2A Solving the quadratic equation for sinA, we get SinA = sqrt(5) - 1 / 4 Therefore x = 15 cos72 = 15 sin18 = 15 . sqrt(5) - 15 / 4
@@DJreeik It's just a different way of simplification, we do cancellation, he just divided both sides by their LCMs.. I found that interesting :) Also sorry for the late reply
Why do all indians say this, they have some obsessive desire to impress people by flaunting their "advance" math, it's not supposed to be a hard question, its part of a rapid fire MCQ set in the SAT.
15 garbage 72 is the only logical answer from this multiple choice even if you dont know how to solve theres no way to get 6 and 72 in the equation so abd is out by means on process of elimination 😂. Work smarter not harder. Which for this example theres 3 ways to do this, 1 as mentioned above, 2 ask yourself why is everything ending in 72?, 3 why is 15 by itself with the cos and if you were to try and figure this nightmare out -> how would you get 6 from 15😂
you can also think:"where tf does the 6 come from"
it’s probably supposed to be a 6-8-15 triangle but the answers are so bad 😂
i know right LMAO, this one really was a no-brainer
😭😭
Out of his ass
If you do it with the law of sines, the 6 comes from dividing the 90° angle by the side length of 15
As a mechanical engineer I use this trick on a daily basis
I wouldn’t call it a trick
How is it a trick? lol
This isn't a trick lol
As a mechanical engineer myself there's no trick and its grade 6 math. The amount of math you take you don't even stop for 5 seconds to think of a problem like this.
@@evo3481 grade 6? In the US we don't learn trig functions until grade 9
or you can also use "I haven't chosen c in a while"
Real
Never said it as a full "sohcahtoa" it sounds nice
Really??
@@aiden_rock yep, no teacher ever said it like that to our class
@@Vullifer1074 what did they say then? Did they just spell out the whole thing?
@@expiredmilk5435 my teacher didnt say anything, just wrote it out and told us to remember it.
I wanna tell what we use here P B P H H B nemonic Pandit Badri Prasad Har Har Bhole(Indian nemonic) where 1)P/H is sin .2)B/H is cos .3) P/H is tan
Thank you makes so much more sense keep doing this
If you look at the triangle inside a circle where the hypp = radius
And you know that youre looking for x aka the adjacent you know its cosine.
And the length of it will be cos(theta)*radius
Therefor 15*cos(72°) ...
Just by a glance you can get all the sides.
|\
| \ cot x
c|___ \
s| /| \
c| / | \ tan x
|/x°_|____\
sec x
Inner triangle ( hyppotenuse represents radius)
/ |
/ |
Radi / | sin x
/ |
/_X°____|
cos x
Unappreciated
Thanks!!!
Wow The fact that you have drawn the triangles
BRO THE DEDICATION💀💀💀
What ru on abt
I learned more in your short video than I have watching long videos all week. Thank you just trying to refresh my memory on trig.
Trig functions are based off of tens….7071, 45°, 70.71 feet..
Bruh, I turned this into quadratic equation
Haven't needed this since i was 13, thanks for the recap.
Im recently learning trigonometry
Any **right triangle problem. Not for all triangles.
i understood it a little but, tbh the reason im so bad at math is because right when im beginning to understand and it clicks for me the teachers go to fast and i get confused
We can see that sin 72 = 15/ x
So x = 15 sin72
Cc thanks sir 🙏💯 ever best teacher
Thank You
tangent b.. hyp x cos.=altitude
Its so hard here in my place in philippines to easily memories math cause they're speed running it other than asian country
It didn't speedrun.
Actually we're late
@@codexcodexcodex yep also because of pandemic
@@norman783 yes, very true
It's easy, I love Math. napakadali lang kung itututok mo buong oras mo sa Math. Self Study lang kailangan.
@@Monkey_Luffy01 Im addicted to music btw
Thank you very much.😊😊
Is there a reason why there's 6 in all the other options?
thanks!
Me as Indian watch this question and answer is ready without even reading the question only from image I have done 😂
Yeah these Americans have it easy yk
In there exam papers, they have multiple choice questions AND they’re easy ass questions like this one 🤯
They complain about how hard school is when they’re the luckiest
@@DJreeik but if your not taught at the level you are then you can't get it right
Or it's harder
@@DJreeik true but we can't deny the fact that also usa children are way more competitive when we talk about Olympiads
Wish Britain had more multiple choice questions
i am dutch and i can follow this thx!
It's a trick question! The answer should be "None of the above", b/c when an angle doesn't have the degree-symbol (the little circle at the upper-right corner), it means that the angle is IN RADIANS (or a pure number, with no units/dimensions). So NONE of the choices is correct. The correct answer is 15 cos(72 deg) which is not the same as 15 cos(72) = 15 cos(72 rad).
[Sorry, I couldn't resist... LOL! ;-)]
Fair enough
True
Could do sine rule as well
That trigonometry is far beyond this level of a question
How?
@@ensign4740 the sine rule isn't needed for right angle triangles. If they were referring to sine itself yeah it can be used, but probably shouldn't for simplicity sake
@@ensign4740 180-72 = 108
108-90 = 18
(The side opposite angle 90)
X I forgot what the number is
----- = ------
Sin(18 Sin(90)
Then just make X the subject then yeah…
@@DJreeik And how do you get to the answer C?
I always forget this
You can literally every question is swap the denominator [only if one has a number and top doesn’t] bring the denominator forward and put it in front of the sign and your done
As an JEE aspirant I don't even need a pen to solve this.
🤦
Bros saving america
15sin18 = x ///// sin(£)=opp/hyph
I got it in a second and I’m in 7th grade, the only trick is to just remember the equations eg in this question adjacent= cos of angle times hypotenuse
Measure it 🫣
Tape measure
You could also use the foolproof trick of "C for Christ"
Hey loved the vid,
Chat I have an odd question, can someone give me a random middle school, 8th grade math problem? For my niece but we made a bet, if someone from chat sends her a Math problem and if she gets it right I have to buy her all the cookies and cream ice cream that'll fit in the deep freeze and it's only half full.
If she gets it wrong then she gets to help me clean my
Ninja ZX6-R
and
Yamaha YZ 250 GYTR. And I mean deep clean and refine to pristine shape. I ain't maintained them in over 2 months 😅😅😅
If your still reading you have my respect.
✌️ Y'all
Could you not do x/sin18 = 15/sin90 then use pythagoras theorem to find the length of the opposite? Pls tell me if im wrong.
Hi..
I am from India
Love you so much
Also equals 15sin18
how would you know if the x goes on top or bottom of the 15
Damn I remember when I was able to do this in my head, now it's just a foreign language
Some people are too fortunate 😕
In the end, is there no way to find the actual length? Instead of saying 15Cos(72)
I’m 9 and I need to learn this for school 😭
My fellow geniuses will pause and screenshot at the end😂😅
this is a no brainer just think "where the hell did the 6 come from*
what happened to the 6
Not for ANY △'s. That's for RIGHT △'s only.
15 cos (72) ≠ 15 cos(72⁰)
True
15cos(72)
So is it basically" what u need and what u have? "
15[cos(72°)]
How to solve any triangle problem it says, yet this method only works for a right angle triangle...
Grea
👁️👄👁️....what the heck did he say ...
Finally, a 'challenging' sat question.
this is challenging ??
My brain immediately saying that X = 9
Bro I didn't look at the options and found the solved to find the value of cos 72.... I first use the fact that cos 72 = sin 18 by trigonometry of allied angles. And then,
if we consider A = 18,
2A = 90 - 3A
》2sinAcosA = cos3A = 4cos^3A - 3 cosA
Knowing that cos^2A = 1 - sin^2A, we get
2sinA = 1 - 4sin^2A
Solving the quadratic equation for sinA, we get
SinA = sqrt(5) - 1 / 4
Therefore x = 15 cos72 = 15 sin18
= 15 . sqrt(5) - 15 / 4
Which is choice C, circles all the letters
It's tough concept
👍🏻
Piersons was so good but lexis definitely looked like the SpongeBob character overall I think Pierson won
That was a complete new way to solve it thanks man
This is the only way to solve it…
@@DJreeik umm actually the way they apply division is different here in my school so this helped me understand better
@@phenyle.ke.nashee Explain what the difference method is plz if I don’t mind
@@DJreeik It's just a different way of simplification, we do cancellation, he just divided both sides by their LCMs.. I found that interesting :)
Also sorry for the late reply
🤓🤓🤓🤓🤓🤓🤓
can somebody explain me how he got 15cos72 with the times 25 cause im still lost but understand a little (im new to this topic)
Is this the where the real sat comes in
Thi method is only suitable for right angled triangles NOT ANY triangle!!
JEE students thinking ...
Why this guy using pen for this 😂😂😂
where u get that cos? Mb
I would do different.
C, before he show his answer
Yeeeaaa. I get it!!!!
9
Sir Can U Solve This Maths Problem Without Formula.,.?
(67⁶⁷+67)/68
it Gives The Remainder 66
could presenters drop the self encouraging 'go ahead' ?
C... Hello. Tashkent sity. Uzbekistan...
C.
Let's go back to grade 9
Grade 8 bruh that’s when you learn geometry, along with trig
I have it in germany and I am currently grade 10
Seriously, are you ever going to do one where the answer is not c)!
I say 15×(sqrt(5) -1)/4
How to solve any problem on test: pick c
why 15
9?
The option is too easy for me
E
Z
Nice try, actually its 15sin(162) haha! Ya almost got me there! 😅
What? The sides involved are Adjacent and Hypotenuse.
This meter is fenced. Measuring 4 squares in acres in relationship to one another and not each other or else you should measure space or league...
Remember he asked for VALUE
The equation is proving an illegal Gravity(verb)
The solution is measuring with a new meter
X is 4.64
In India trigonometry is sin cos tan
Yeah it is in the us too? NGL don't know what you mean by this
wdym “in india” math is math wherever you take it, + what about sec csc cot sinh cosh tanh sech csch coth?
@@imaboisir7227 he probably means when he said soh cah toa
Wow what a great question 😑 an average Indian student of 10th standard would take 10 seconds to solve it. It is so difficult 😒
It’s not meant to be difficult, moron.
Bhai muje kitna confusing lagra tha
@@phenyle.ke.nashee 🤔 Bhai trigonometry padho hai ki nahi 🤔
Why do all indians say this, they have some obsessive desire to impress people by flaunting their "advance" math, it's not supposed to be a hard question, its part of a rapid fire MCQ set in the SAT.
@@ayushsingh3484 padh raha hu
Where is E. I am not bothered
Meanwhile Asians solving this in their head and writting answer directly..❄️
Am I wrong? SOH CAH TOA only works with right triangles?
You’re correct
This is a right angle triangle indicated by the square denote on the bottom vertex. Sine or Cosine Law for all other triangles.
I solved this in like 10 sec in my head and I'm 8n y8
JEE student be like : What's this kid 😂
Why didn’t he use SOH cause adjacent is unknown
because that's not how trigonometry works?
This only applies to right triangles though
ye, and this is right triangle :D
Writing in an iPad is so satisfying. I would literally practice problems for hours only if I had one 😩
X is equal to 9
15 garbage 72 is the only logical answer from this multiple choice even if you dont know how to solve theres no way to get 6 and 72 in the equation so abd is out by means on process of elimination 😂. Work smarter not harder. Which for this example theres 3 ways to do this, 1 as mentioned above, 2 ask yourself why is everything ending in 72?, 3 why is 15 by itself with the cos and if you were to try and figure this nightmare out -> how would you get 6 from 15😂
As a 6th grader, I’m pretty sure I could understand most of it since I’ve been learning all by my self