Length of an arc that subtends a central angle | Circles | Geometry | Khan Academy

Missed the previous lesson?

Geometry on Khan Academy: We are surrounded by space. And that space contains lots of things. And these things have shapes. In geometry we are concerned with the nature of these shapes, how we define them, and what they teach us about the world at large--from math to architecture to biology to astronomy (and everything in between). Learning geometry is about more than just taking your medicine ("It's good for you!"), it's at the core of everything that exists--including you. Having said all that, some of the specific topics we'll cover include angles, intersecting lines, right triangles, perimeter, area, volume, circles, triangles, quadrilaterals, analytic geometry, and geometric constructions. Wow. That's a lot. To summarize: it's difficult to imagine any area of math that is more widely used than geometry.

About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.

For free. For everyone. Forever. #YouCanLearnAnything

Subscribe to Khan Academy’s Geometry channel:

[fantasygurus]

This dude is the type of guy who says, "can you do me a flavor?"

[jackiec]

Love Khan Academy. Makes this problem seem like common sense :D

[CharlieKaneSeattle]

Helpful for a problem I am working on right now.! Thanks Khan Academy

[Dani]

Thank you so much! This was extremely helpful!

[Floydknight]

The guy narrating sounds like Boffy if he was a commentator for a golf tournament

[jomm.-.]

what do we do if the only given is the radius and the central angle?

[andrews]

has a newer version of math came out since this video was made?

[MathematicsFoundation]

why the ratio you taken is equal?? How?

[kundankumar-hjdz]

find the arc length of r theta=a for r=a to r=2a

[anantchaudhary]

This video was super helpful to me. It helped me with the exercise that i was doing.

[gabysavvy]

For the second one I keep on getting the wrong answer of 54...I put 35 times pie divided by two. I don’t know we’re I went wrong help

[rexr]

I love math and im good at it but when my teacher gives us 1 week to learn an entire chapter and have a big test on it then im dragged to here.

[caseykuang]

Did anyone else hear people talking in the background? Am I schizophrenic?

[sychomadman]

Can anyone explain what happens if there are a lot of lines within a circle that it gets freaking complicated? :/

[ethiotiktok]

you didn't proof how the central angle is the subtended arc which doesn't make any sense

[TheNickster]

lol Am I the only person here who hates math?

[goodluck]

@ 4:39 How are you getting 0.5pi from pi divided by 2? It's not It's 1.570796237...

[shitonastick]

is it me or does the finger piss you off. Either way, good video.

[CharlieKaneSeattle]

Helpful for a problem I am working on right now.! Thanks Khan Academy