For me, I believe that this is more like a review than anything because if you are a complete beginner then there is a high chance that you don't understand like 90% of the video. If you are currently being taught geometry area then this is completely useful as a review if you dont understand it. This is because you probably already know the orgins of pi and the formula, but dont actually know how to find the area. Btw, thanks Mr.Khan, the video was useful.
@lightdraw The formula for the area of a circle can be derived by integrating the equation of a circle using the methods of calculus. It is very complicated for some people to understand and requires advanced integration techniques, which is why the formula is generally accepted and rarely explained.
My suggestion: By definition, c = 2*pi*r. Examine regular N-sided inscribed polygons / circumscribed polygons: they are composed of N triangles, and the ratios of the areas of the polygons to their perimeters appear to converge to r / 2 as N goes to infinity. Try to prove the perimeters P(N) converge to c and the ratios R(N) converge to r / 2. For the latter, examine the region between the inscribed and circumscribed polygons and use the Pythagorean theorem.
I know a thing that might help you guys: Cherry Pies are Delicious ~~ Circumference=pi x diameter ~~ C=pi D And for area: Apple Pies aRe Too~~ Area=pi x Radius squared ~~ A=pi R² I hope you understand this^^
@@Ash-eb4en he explained pretty well. Hes not just explaining the equation, but hes trying to show you why and show you connections. "Any fool can know. The point is to understand" - Albert einstein Radius x radius gives you a square. The reason you multiply it by 3.14 is because 3.14 basically cuts off the unnecessary bits of the squares to get only the area of the circle. The real question is how did they find 3.14
ok i found it what it ment, but lets take an exampel, on my calculator and when doing it on paper, for eaxmpel radius is 3, then the areal should be 28.26 but on a site online it says its 28,27 and on my calculator it dosent show 28,2626262626 so why is it rounded up? PLEASE PLEASE PLEASE EXPLAIN TO ME!! :(!! Thanks!
+kittycat meowface I bet this is pretty late, but you divide the Diameter by 2 to get the Radius. ex: Diameter = 8 Radius = ? Radius= Diameter/2 Radius = 4
I had to read this before i seen 10[] was 10x10=100 duh.. Explanation: The circumference of a circle is given by formula: 2πr So, 2πr=20π 2πr=20π r=202 r=10cm(assuming the units to be in cm) The area of a circle is given by formula: πr2 Where, π has a constant value of ≈3.14 and r denotes the radius. The radius of the circle =10cm The area =πr2≈3.14×(10)2 =3.14×(100) =314cm2
Excuse me Kahn Academy or anybody really what does it means when it says what is 25% of the area in a circle or really any other circle hope someone answers :/
"It doesn't look like a perfect circle, but we can use our imaginations" 😂😂😂😂
Itzel Luna yea laughed hard though😂😂
Itzel Luna you right, using our imaginations is awesome isn't it
Andrew Do Ikr
lol
Itzel
Thats amazing to hear you heard somerhing we all heard
And you are pointing it out like we were deaf at that moment.
For me, I believe that this is more like a review than anything because if you are a complete beginner then there is a high chance that you don't understand like 90% of the video. If you are currently being taught geometry area then this is completely useful as a review if you dont understand it. This is because you probably already know the orgins of pi and the formula, but dont actually know how to find the area.
Btw, thanks Mr.Khan, the video was useful.
+Code Battle Seraph Theres a video before this explaining everything else
In 6 minutes. I understand better than what my teacher taught from 2 weeks
Best teacher ever:)
I understand everything he teaches!:)
Totally agree, even for people that English is not their native language like me
Thanks so much! I got 97% in my Math :)
me tooo!!!!!!!!!!!!!!!!!
camille torres I got 88% last time I watched his videos
I should continue O_o
Me three!!!
SaME SScoER
I can’t believe it
It is too hard to under stand explain one thing instead of jumping around.
Thank you so much, I have a final exam tomorrow, thank the lord for you!
Thankyou Mr. Khan it's very helpful and it made me recall what I learned when I was just in elementary.
HAHA...I still don't understand..0-0
Hello fellow 7th graders
Hi
Yo
I take 6th Grade Challenge Class so I do 7th grade math
Hey
Hey
¡Muchos gracias señor!
I listened to my teacher I didn’t understand anything then I watched this video and as usual I got the formula
Yasssss this is what i needed he explains so well and he is well educated i trust that this is the correct method
Thank you! I finally finished my math homework!!! :)
Thanks I needed help on my homework
u are the best sir EVER!!
Doing middleschool homework pa I just need a refreshment
Khanaacademy ur the best what i see....
wow i was four when this was made and now i need it for my geometry class
lol same
I was just born when this came out HOLY SH*T
Thank you very much. It is just empowering.
@lightdraw The formula for the area of a circle can be derived by integrating the equation of a circle using the methods of calculus. It is very complicated for some people to understand and requires advanced integration techniques, which is why the formula is generally accepted and rarely explained.
I used to watch and solve the website questions so much.
lol theres me learning again since i forgot
+Khan academy i wish you were my math teacher!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@Allison Veronica *lies*
So does that mean when we find the area of the circle, we multiply that area number by 3.14 and that's your answer?
Man, way easier than i thought! Thanks!
can u do a video about pattern and inductive reasoning?? im stuck on this
Just what I needed. :-) Thank you.
My suggestion: By definition, c = 2*pi*r. Examine regular N-sided inscribed polygons / circumscribed polygons: they are composed of N triangles, and the ratios of the areas of the polygons to their perimeters appear to converge to r / 2 as N goes to infinity. Try to prove the perimeters P(N) converge to c and the ratios R(N) converge to r / 2. For the latter, examine the region between the inscribed and circumscribed polygons and use the Pythagorean theorem.
You make it a lot easier.
a playlist devoted to pi sounds very interesting. :)
thanks now i understand way better
Thanks this really help me for my next exam
this really helped me! thank you!
Lauren Yates hi
thank u , it helped me a lot
I know a thing that might help you guys: Cherry Pies are Delicious ~~ Circumference=pi x diameter ~~ C=pi D
And for area: Apple Pies aRe Too~~ Area=pi x Radius squared ~~ A=pi R²
I hope you understand this^^
you made me more confused
The subject is simple by its own. Don't try to put water on a full glass
(￣ー￣)
Instead of putting the value of pi as 3.14159 we can put it is 22/7 to be more accurate and the solving the area and perimeter of a circle is easier
im a 6 grader and thats the best way u coulda do this thanks...
Anita jeff I'm a 5th grader and in 2 days I take my pre PSAT test. I am freaked out. I'm scared that I am not going to know anything.
how did get 100 ? woudn't you do 3.14x10 ? witch equals 31.4?
Nice Video
Good job done thanks lot...
Thx for liking whoeve you are
thank you. never knew how to do it (well, remember it actually)
5 stars!
jonjonjon1370 how a comment thats nine years old and has no comments or likes
Well thats why im here
To comment
1 question. The area is 100 pi or 100 pi with the square power
So if I have 3/4 of a circle n the diameter is 20cm , what's the area of the figure in terms of pi ?
Are you playing a shooting game? Why is your cursor a crosshair?
Fantastic! Thank you!
His voice is conforting:)
How would you determine the circumference of an oval would be? is there a mathematical formula for it?
Thank u:)
next
Just aswered my whole hw Thx
thank you, very helpful
good one sal
Netherlands team sucks
So basically it's radius x radius x pi
Yes
Oh thabks i needed that
Exactly
Thanks for clearing things up. He gave a whole 6 min speech and u cleared it up in a sentence. 😂
@@Ash-eb4en he explained pretty well. Hes not just explaining the equation, but hes trying to show you why and show you connections. "Any fool can know. The point is to understand" - Albert einstein
Radius x radius gives you a square. The reason you multiply it by 3.14 is because 3.14 basically cuts off the unnecessary bits of the squares to get only the area of the circle. The real question is how did they find 3.14
I love it 😻
Thank you!!!!!!!!! My god ur AWESOME
Inv1ctus ihas
how do you prove that the area of a circle is pi*r^2 please reply
What if r is 0.05m vs 5cm? I'm getting 0.00785m^2 and 78.5cm^2, which are not equal... :/
Anyone else in quarantine having to do online homework sure Monday (today)
Sam
Same*
Silas Reese I have to find the area of trapezoids which isn’t bad but my Ela and Docal studies/history teacher is making me do slides
is there a playlist that is purely on pi ?
ok i found it what it ment, but lets take an exampel, on my calculator and when doing it on paper, for eaxmpel radius is 3, then the areal should be 28.26 but on a site online it says its 28,27 and on my calculator it dosent show 28,2626262626 so why is it rounded up?
PLEASE PLEASE PLEASE EXPLAIN TO ME!! :(!!
Thanks!
Going a little bit fast for us slow folks. Watched this and the other PI video several times....Will watch several more.
how do you get 3.14159 times 10 to 10 times ten plz answer
❤️❤️
This was helpful
this really helped thank you 😀
thx. was really helpful
"Its just a number but its a magical number" lol
you are the best
cool videos
If anyone need any further math help, no matter the subject or difficulty level, let me know and I’ll do my best to help (quickly)
:D
Helpful
What if you have the diameter of a circle and are trying to find the area?
+kittycat meowface I bet this is pretty late, but you divide the Diameter by 2 to get the Radius.
ex: Diameter = 8
Radius = ?
Radius= Diameter/2
Radius = 4
+Mishal Montaner thanks
how did you get 4=r ?
thank you for this
I A LOVE MATHEMATICS AND SCIENCE TO AND PLEASE TEACH ME MORE OF THIS PLS PLS PLS! :D:D:D
If only i liked math....
I have the same question. I kinda got lost were he put 16=r2 the he put 4=r
4 times itself
twice which is what ^2 (Power of two) means. 4x4=16
he is amazing
This confused me even more *face palm*
Thanks Khans academy
I had to read this before i seen 10[] was 10x10=100 duh.. Explanation:
The circumference of a circle is given by formula:
2πr
So, 2πr=20π
2πr=20π
r=202
r=10cm(assuming the units to be in cm)
The area of a circle is given by formula:
πr2
Where,
π has a constant value of ≈3.14
and r denotes the radius.
The radius of the circle =10cm
The area =πr2≈3.14×(10)2
=3.14×(100)
=314cm2
Where tf did the 9 come from
It's far from what I was taught at our math subj so i'm confused on what to do
It took 2 minutes to get to the real work. You're explanation is too complicating to understand.
Lol
Na u Just slow
thank you :')
I love this guy xD
real big help
my favorite thing is to look at the comments on a math video.
Can someone please explain me what r2 means... ?
great vid
the people who disliked this video probably ment to say dis i like
🤸💙🙏🙌
Why is 3m in brackets? 2:35
Putting brackets is another way to say, multiple
How the hell do you go from (10)2 to 100
10x10=100. It wasn't 10x2 it was 10^2 or 10 squared. You probably haven't been taught squares and stuff yet so don't worry about not understanding,
Thx
BUT I CAN'T USE PIE IN EXERCISES.
O Goku faix em inglês tmb :0 chocada
good
do u have new videos
Excuse me Kahn Academy or anybody really what does it means when it says what is 25% of the area in a circle or really any other circle hope someone answers :/
You find the area of a circle and find 25% (of the area that you calculated)
ty c;
This guy just keeps jumping around all the time!