# How to Find the Circumference of a Circle

It doesn’t matter which formula you use as long as you use them correctly.

Consider buying an advanced calculator that already has ? as one of the buttons. This will allow less typing for you and a more accurate answer because the ? button produces an approximation to ? that is much more accurate than 3.14.

Here are two formulas that are usually used:

If you know the diameter, use the first method. However, if you know the radius, use the second method. Remember that you can still calculate the diameter or radius using simple multiplication and division (see “Diameter” and “Radius” above.)C = pi x Diameter or C = pi x(2 x Radius)Plug in your numbers and solve.

This how to find the circumference of a circle tutorial helps you to understand the different parts of a circle first. There are two equivalent formulas for arriving at the circumference of a circle. However, either one will allow you to find the circumference. The formula for circumference is pi x Diameter. It can also be written as pi.d.

Understand the different aspects of a circle.

Circumference is the distance or length around a circle. This is the answer to the equation you are trying to solve and train yourself on how to find the circumference of a circle.

The symbol like this ?(pronounced like pie, but spelled pi) is an irrational number, which means that it cannot be written as a fraction like 2/3 or 1/2.

Also, if you write pi as a decimal, it never ends. A good approximation of pi is 3.14 when used in formulas. Some graphing and advanced calculators may have the pi symbol on the keyboard. Note that ? is not anywhere in the circle but is essential when calculating the circumference. The center is the exact middle of a circle. If a line is not touching the center, then it is a chord. A chord is any line in a circle that touches two different points. It is easier to find the diameter and radius if you know where the center is first.

Diameter is a line that touches two ends of circle and the center you will use this line, or the radius, alongside with ? to calculate the circumference. Multiply the radius by 2 in order to get the diameter.

Radius is a line that touches an outer part of the circle and the center. It does not make contact with more than one part of the outside. You can replace diameter with this for an alternative formula. Divide the diameter by 2 to get the radius.

Replace the diameter or radius with the diameter or radius you are given.

Example: If your diameter is 6 then plug in 3.14 x 6. This will equal 18.84.

Example: Following the first example with the diameter being 6, you can calculate the radius and use that as well. The radius equals 1/2 of the diameter so radius equals 6 divided by 2. That equals 3.Now you can plug 3 into the formula. 2(3.14) x 3 which is also equals 18.84.