Area of a Circle - Quick Visual Proof

This easy visual proof shows that the area of a circle is πr2.

[math]

great job explaining with this visual proof, thanks for sharing

[IS-pydk]

This was way easier than what my school taught me 😀

[Metal-Josh]

A little late, but I've spent 20 years, since high school, and never got why that is til now. Thanks, I liked that

[MickDavies]

I guess I'm going to go to Yatala Pies this week after this episode and all its pi talk!

[tracyrain]

So glad you never touched on Pythagoras! Still have PTSD from a teacher about that! Really interesting proof, though. Tyfs. 😊

[lauramariawaugh]

Great tutorial thank you.
Incidentally, you look very like I imagined from hearing your voice! I thought you were very blonde though. 😀

[abishangamez]

btw josh (tecmath) why is it tecmath not mathtec?

[vijayakumarit]

This video is very helpfull I learnt a lot s sir🤘

[johnryder]

You should call it the tree ring method Josh

[yhc]

I clicked cause you were in the thumb. This is a great visual method amd should cut thru some clutter. I enjoy your teaching method and I'm guessing your full time job is a math teacher at the high school level.

[july]

For me simple math was always easy to understand. So this video wasn't a big opening for me. I study way harder math now and that's where I have a problem XD

[tenmiltenmil]

August 26th Thursday 2031
I used to know this stuff !
🧐🧐🧐🤔🤔🤔🤨🤨🤨❤️❤️❤️👍👍👍♥️♥️♥️

[GreenAppelPie]

But but pies are round lol 😂 that never gets old

[meongkucing]

This sound like Boris johnson.
Maybe he deserve become a teacher math.😂😂😂

[loadapish]

Im so confused. What does pie mean? Pie r and pie r squared... i feel like someone just blended ma brain with one of those kitchen blenders

[sailbyzantium]

I'm not at all clear how the rectangles were derived. Yeah, they are pulled apart from your concentric circle lines, but how do you know what their heights and widths would be--esp. as informed by a measurement using an irrational number? And for the last rectangle it seems impossible that its side length would be 2pi*R. That's the entire length of the circle's outer perimeter. If you are going to fashion a rectangle out of that, then its entire perimeter would equal 2pi*R and not just one of its sides. Confusing and unclear.

[cobra]

If I want to know the area of a circle, I multiply the diameter times .7854. Done one step. I am lazy.

[billyandrew]

You lost me there.
The only subject I was never able to pick up in school, beyond add, subtract and multiply, due to a physically and mentally sadistic Maths teacher, and you talk as if I already knew pie r squared, etc.
The add, subtract, multiply tricks you show are brilliant, but this stuff is too much to take in.
Now in my 60s, I probably wouldn't need it anyway, beyond using a tape measure and maybe my self made large compass.
Thanks for uploading.

[thoughtfortheday]

I reckon this video was really interesting but I have no way to know as the broadcast volume was too low. A shame, I gave up as the struggle to hear was too frustrating.

[orac]

Incorrect. Circumference is a finite number eg 20cm but pi is an infinite number so if you multiply an infinite number by a finite number the answer is infinite so circumference will never be correct.