And I were to tell you that its circumference is equal to 10 meters that's the circumference of the circle.

I know how to calculate the area of a circle.

Circumference

Epicycle

Pi

So what is the circumference?

Epicycle

let's call this d1 nope, too thick let's call that d1, this is d2 that that's going to be equal to a constant number along the whole ellipse.

Of course not.

Do it mathematically correct.

Maybe it's 3 meters put some units in there.

So if you were to get your tape measure out and you were to measure around the circle like that, what's that distance?

My volume is going to be 4 3...And then I don't want to just put a pi there because that might interprit it as 4 divided by 3 pi.

We sat around the fire in a circle.

The cattle just keep calmly walking thinking they're going in circles and following their buddies.

I can draw a neater circle than that. So let's say the circle loks something like that.

He's reciting the digits of pi.

Start transport from this point of the circle

We sat around the fire in a circle.

Select a point on the circle...

Transport a measure on this circle

Select the segment to transport on the circle...

And so for area we need to know the radius 'cause area's pi R squared, so we can figure out the radius from the circumference by saying, well circumference is equal to two times pi times the radius of the circle, or if you say 36 pi, which we were told this is the circumference, is equal to two times pi times the radius.

That's going to be the exact same thing as the circumference of either the top or the bottom of the cylinder

And let's say when their tape measures weren't so good,

OK, that's interesting.

Let's call it area surface.

Actually, never!

It's that x point that we're evaluating it at.

If it hits something you people see that?

What about bigger numbers?

Pi's just a number.

Circles around the Origin.

And you can actually go beyond that.

It'll be the circumference of this ring times it's height.

Come along.

Do you also mean that is to complete our life?

Since Archimedes, people all over the world have been obsessed with calculating Pi.

So it's just going to be 3 times 2 or 3 plus 3, which is equal to 6 meters.

A good man... draws a circle around himself and cares for those within.

OK, this is a neat property of circles.

If we do it with radians, we know that each revolution is 2 pi radians

With that out of the way, let's just apply this radius being 7 centimeters to this formular right over here.

So we're going to have a volume is equal to 4 thirds pi 7. cm 3.

Now, it's obvious that a circle's circumference would get smaller or larger along with its diameter, but the relationship goes further than that.