And now we're going to look at how to draw circles of different sizes.

Here, I still have my code from drawing a triangle, a square, a pentagon,

and a hexagon.

We're going to use ideas from these to draw a circle.

So let's check that they all still work--

a triangle, a square, a pentagon, and a hexagon.

And in each of these, we turn a total of 360 degrees.

So we're going to want to turn a total of 360 degrees for the circle as well.

Let's start off, and let's only turn one degree.

And to turn a total of 360 degrees, that means we'll have to repeat 360 times.

Because 360 times 1 is 360.

OK.

Let's try that.

Oh whoa-- 360-- repeating 360 times means that we have 360 sides,

and each of those is 50 wide.

So the cat went off the screen.

It just did crazy things.

So I think 50 steps is too many.

I have my clear script here, so I can press space and get

everything cleaned up.

These are really, really helpful.

So instead of moving 50 steps, let me just try moving one

and see what happens.

Looks good.

Now if I want something bigger, I don't want to do something like 10.

10 would be way too big.

Let me look at even how much bigger 1.5 is.

Because we had 360 sides, even increasing each side's length by 0.5

really changes the size of the circle a lot.

I can also make something smaller by just moving 0.5 steps on each side.

We can think about how big this circle is

going to be by thinking about the perimeter.

So when I move one step each side, I repeat that 360 times.

So the perimeter is 360.

If I move two steps on each side, I repeat

that 360 times so the perimeter is 720.

So you can see by multiplying these numbers

how much it's going to move total, and that

will be the perimeter of the circle.