You want the formula for the diameter (2r) if you have the circumference? If the formula for circumference is 2(pi)r, you simply do the algebra to determine r c=2(pi)r. Divide both sides of the equation by r and you have c/r=2(pi). Then divide both sides by r and you have c=2pi/r

D=C/pi

Roughly 2.5 feet.

I don’t have the circumference or thd diameter. All I have is a straight line that needs to be bent onto a circle.

That’s what I came.up with too @seawulf575. :( not big enough.

about 90 Barleycorn.

I see ya 90 barly corn an raise ya a bushel of sprouts!

The circumference is the length of the thing. It will still be as long whether straight or in a circle.
In this case, 8 feet.

Guess I need to tie 2 together to get the diameter I want.

@Dutchess_lll

What diameter do you want?

You have the circumference, you want the diameter which is twice the radius (2r). As long you know any 2 of the 3 measurements, you can juggle the c=2(pi)r equation to determine the 3rd.

I have an idea for a firepit guard Brian, to keep kids safe. Firepit sizes vary though so…IDK. At least 4 feet.

I looked at my first answer and it’s all fkd up. There’s an inadvertent r on the left side of the first equation.

That’s ok StanlyMan! I had a Eureka moment….portable.do fencing! They come in different sizes.and they’d be a lot more stable than a circle.

@Dutchess_lll

Then the minimum length you need is 12’ 7”.

Multiply the diameter you want by Pi. if you want 5 ft, multiply by 3.14 to get 15.7 ft. 15 ft 8½ inches. Call it 16 ft. You’re not building pianos.
~Or convert it to Barleycorns.—> 563 barleycorns

Loll @Luckyguy!

I think a portable dog fence is a better answer. It’s already made and more stable. Lot less expensive and a LOT less work.

Is it a circular dog fence, if yes what’s the diameter, if not what’s the perimeter?

But it doesn’t have to be circular @Pinguidchance. I was stuck on that because firepits are circular. I’m finding octagonal dog fences with adjustable panels that might be the ticket. Have to wait till I get home to research down to the bone.
I just had a young mother damn near give her 2 year old a spiral fracture on the his arm last night when she finally got off her ass to yank him away from the fire.
Gotta come up with something.

Just had it right at approximately 2.5, @Dutchess_lll

The formula is: C = 2(pi)(r), and we know that C = 8.

8 = 2(3.14)r
8 = 6.28r
1.27 = r

d = 2r
d = 2.54

See guys…. it’s not even that complicated. Just 8 / 3.14. That’s all.
I’m not building a piano!

You could say (more accurately) 2.546 ft, but the contractor would laugh at you.

2.546…