Easy math question (circumference of a circle)

How do i calculate the cirmference of a circle if i know its radius
And another question how do i calcuulate it if i know its diameter?

How do i calculate the cirmference of a circle if i know its radius
And another question how do i calcuulate it if i know its diameter?

Richboy96

Inscribe a regular polygon in the circle and take the limit of the perimeter as the number of sides approaches infinity. thriteenthmonke

Wouldn't the number of sides be a constant?

Let me google that for you

Let me google that for you

_en1gma_

Let me google that for you

_en1gma_

[QUOTE="_en1gma_"]

Let me google that for you

Richboy96

Yes, actually.

[QUOTE="_en1gma_"]

Let me google that for you

shahchip

[QUOTE="_en1gma_"]

Let me google that for you

Richboy96

[QUOTE="_en1gma_"]

Let me google that for you

Richboy96

Just to clarify, commonly you will see it as 2*pi*r, not 2 * D, even though it's the same thing.

-Betta

2*pi*r i believe. something like that anyways

You need help if you can't comprehend pre-algebra.

With radius: C=2(pi)r

With diameter: C=d(pi)

Where "d" is the diameter and "r" is the radius.

Lol does that actually work?

Wouldn't the number of sides be a constant?

Xeros606

[QUOTE="Xeros606"]

Lol does that actually work?

Wouldn't the number of sides be a constant?

thriteenthmonke

Dude, that's easy as PIe ;)

What you do is find the arc length of one quarter of the circle and multiply that by 4. Use the equation for arc length s = ϴ * r, where ϴ is equal to the angle in radians (in this case ∏/2), r is equal to your radius, and s is equal to your arc length.

If you only have the diameter, divide that by 2 and that is your radius length.

try the pythagorean theoremget-ka12

As has been said, this is what Google was made for. :P