Generally speaking, the maximum number of links in a food chain is
05
09
07
03

4 and 5

Explanation:

The ratio of C to d. So the ratio of C to d for Circle A would be 12.55 over 4. And using a calculator, we can find that this is approximately, 3.14. Now what about for Circle B? The ratio would be 6.27 over 2.

00:02:35

And with a calculator, we would find that this is also approximately 3.14. How about Circle C? The ratio would be 4.71 over 1.5. Using a calculator to do this division, we would find this is also approximately 3.14. So pi is the ratio of any circle's circumference to its diameter.

00:03:00

And pi is approximately 3.14 or 22/7. Now let's see if we can use what we just learned to develop a formula for the circumference of a circle. I know that C/d is pi. So all I have to do is multiply both sides by d. So I will multiply d on the left. And d on the right. They'll cancel on the left.

00:03:35

And look. I'm left with C on the left-hand side of the equal sign, and pi times d on the right-hand side of the equal sign. This will be our equation, our formula, I'm sorry, for the circumference of a circle. Now let's use it to find the circumference of a circle. So if I know that C is equal to pi times d, in this case

00:04:02

I've been given d as 12 centimeters. So let's substitute that diameter in our formula. So C is equal to pi times 12, isn't it? I'm going to put the 12 in front of the pi. So the circumference of this circle is 12pi. The circumference here have been given in terms of pi, meaning that I've left the symbol for pi in the answer itself.

00:04:32

And we also have a unit of measurement that we can't forget of centimeters. So the circumference of this circle is 12pi centimeters.

Section 6

00:00:00

TEACHER: Let's take a look at this problem together. How do you find the circumference of a circle using the radius? I've been given this circle, and its radius is 5.5 centimeters. I've also been given two formulas, C equals d pi and d equals 2r. Now, since I know that d equals 2r, I can substitute

00:00:20

the 2r in for d in the first formula. So the circumference is 2r pi. Now I'm going to take the radius I've been given, 5.5 centimeters, and substitute it in for r. Now 2 times 5.5 is 11, so the circumference is 11 pi centimeters. But I'm going to look for an approximate value of pi using 22/7.

00:00:51

So C is equal to, or C is approximately 11 times 22/7. And using a calculator to find 11 times 22/7, I find that C is approximately 34.57 centimeters.

variation is inherited