whats a circumference used in math????????????

Question

please telll me ill pick u as best chosen answer give u the most stars and give u 10 points and give an example and steps

Answer 1

Did you want the DEFINITION of a circumference--because that's all that you asked for in your question!--or did you want something more, such as how to calculate the circumference of a circle, given the radius or the diameter?

Because if all that you wanted was the definition, the the first person who answered the question is correct--that is your answer.

But I'm confused, because you're saying that you want examples and steps, so that makes me think that you're needing to solve a math problem.

If you know the radius OR the diameter of a circle, then you can calculate the circumference using a constant known as "pi."
Pi is a number that is about 3.14...but it can be calculated out indefinitely.
But, for most purposes, all that you need to remember is that Pi = 3.14.

A radius is 1/2 of a diameter. (Put another way, a diameter is 2 times a radius.)

So if your radius is, say, 2 inches, then your diameter is 4 inches.

And if your teacher says that s/he wants to you calculate the circumference of a circle that has a 2" radius (or a 4" diameter), then all that you need to remember is that the circumference is Pi times the diameter, or 4X 3.14 = 12.56 inches.

Answer 2

The distance around a circle is called the circumference. The distance across a circle through the center is called the diameter. Pi (that little symbol that looks like a double T ( TT )is the ratio of the circumference of a circle to the diameter. Thus, for any circle, if you divide the circumference by the diameter, you get a value close to Pi. This relationship is expressed in the following formula:
C over d equals Pi
where C is circumference and d is diameter.

Answer 3

Circumference of a Circle Terms and Conditions For Use | Recommend This Lesson!
A circle is a shape with all points the same distance from the center. It is named by the center. The circle to the left is called circle A since the center is at point A. If you measure the distance around a circle and divide it by the distance across the circle through the center, you will always come close to a particular value, depending upon the accuracy of your measurement. This value is approximately 3.14159265358979323846... We use the Greek letter (pronounced Pi) to represent this value. The number goes on forever. However, using computers, mathematicians have been able to calculate the value of to thousands of places.

The distance around a circle is called the circumference. The distance across a circle through the center is called the diameter. is the ratio of the circumference of a circle to the diameter. Thus, for any circle, if you divide the circumference by the diameter, you get a value close to . This relationship is expressed in the following formula:

where is circumference and is diameter. You can test this formula at home with a round dinner plate. If you measure the circumference and the diameter of the plate and then divide by , your quotient should come close to . Another way to write this formula is: where · means multiply. This second formula is commonly used in problems where the diameter is given and the circumference is not known (see the examples below).

The radius of a circle is the distance from the center of a circle to any point on the circle. If you place two radii end-to-end in a circle, you would have the same length as one diameter. Thus, the diameter of a circle is twice as long as the radius. This relationship is expressed in the following formula: , where is the diameter and is the radius.

Circumference, diameter and radii are measured in linear units, such as inches and centimeters. A circle has many different radii and many different diameters, each passing through the center. A real-life example of a radius is the spoke of a bicycle wheel. A 9-inch pizza is an example of a diameter: when one makes the first cut to slice a round pizza pie in half, this cut is the diameter of the pizza. So a 9-inch pizza has a 9-inch diameter. Let's look at some examples of finding the circumference of a circle. In these examples, we will use = 3.14 to simplify our calculations.


--------------------------------------------------------------------------------
Example 1: The radius of a circle is 2 inches. What is the diameter?
Solution:
= 2 · (2 in)
= 4 in

--------------------------------------------------------------------------------

Example 2: The diameter of a circle is 3 centimeters. What is the circumference?
Solution:
= 3.14 · (3 cm)
= 9.42 cm

--------------------------------------------------------------------------------

Example 3: The radius of a circle is 2 inches. What is the circumference?
Solution:
= 2 · (2 in)
= 4 in

= 3.14 · (4 in)
= 12.56 in

--------------------------------------------------------------------------------

Example 4: The circumference of a circle is 15.7 centimeters. What is the diameter?
Solution:
15.7 cm = 3.14 ·
15.7 cm ÷ 3.14 =
= 15.7 cm ÷ 3.14
= 5 cm

--------------------------------------------------------------------------------
Summary: The number is the ratio of the circumference of a circle to the diameter. The value of is approximately 3.14159265358979323846...The diameter of a circle is twice the radius. Given the diameter or radius of a circle, we can find the circumference. We can also find the diameter (and radius) of a circle given the circumference. The formulas for diameter and circumference of a circle are listed below. We round to 3.14 in order to simplify our calculations.

Answer 4

The circumference of a circle is the length of its perimeter. To understand where the formula comes from you need to have some knowledge of integral and differental calculus.

The formula c=2pi*r (where r is the radius) comes from the more general formula for arc length,
L=integral from a to b of sqrt[r^2 + (r'(theta))^2] dtheta (in polar coordinates).

Letting r(theta)=r (the eqution of a circle), this integral becomes integral from a to b of r dtheta, since r'(theta)=0.

Evaluating this integral will give you L=r*theta where L is the arc length created when the radius is subtended any distance from the reference axis. When you go from a=0 to b=2*pi you get the entire arc length, or circumference of a circle, thus c=2pi*r or c=pi*d, where d is the diameter of the circle which is just, d=2*r.

Answer 5

The circumference is the distance around a circle. For example, let's say you wanted to put a fence around a pond that was 10 feet in radius. You would take 3.14 times 20 and would need 62.8 feet of fencing. C= 3.14 X d

Answer 6

circumference- the perimeter [distance] around a circle

the formula is pi[3.14] multiplied by the diameter[distance across] of the circle

for example if the diameter is 10in then the circumference would be 314in [3.14 x 10]

if you are given the radius the formula is pi x 2r

example - if the radius is 5in

3.14 x 2(5)
3.14 x 10
314in

Answer 7

The circumference of a circle is the distance around the outside of the circle. It could be called the perimeter of the circle.

The formula is pi(3.14)*d(diameter of the circle)
OR
2*pi(3.14)*r(radius=diameter/2)

Answer 8

Circumference is the distance around the outside of a circle.

Answer 9

Circumfrence is the distance around a circle. It's calculated by multiplying pi times the diameter. Pi is a number with an infinite (so far) number of decimal points, but starts with 3.14......etc.

Look up pi!

Answer 10

The circumference is the distance around the circle.