Circle equation I have a circumference circle that is 22 1/2". How do I find the diameter?

1.64 ( C=pi D circumference is equal to pi times the Diameter. Diameter is equal to the circumference divided by pi. pi is 3.14. 5.14 divided by 3.14 is 1.64.)

Circumference of a circle is Pi x Diameter

So divide the Circumference by Pi to find the diameter

630 / 3.142 = 200.5 mm

Circumference of a circle = 2*pi*r or d*pi

where r- radius
d- diameter
pi=22/7

If you would like to know the circumference of a 15" diameter circle this is the formula:
circumference = radius x 2 x pi
circumference = diameter x pi

in our case:
circumference = 15" x 3,14
circumference = 47 ,1" (that's 119,634 cm)

The circumference of any circle is pi (lowercase Greek letter pi) multiplied by the diameter. For a four-foot diameter circle the circumference is about 12 feet 7 inches.

The formula is simply this: C = (pi)d. In this equation, "c" represents the circumference of the circle, and "d" represents its diameter. That is to say, you can find the circumference of a circle just by multiplying the diameter by pi, which is an approximation of 3.14.

If you know the center, measure the distance between the center and one point on the circumference. Measure with the opening of a compass and report on a ruler, or use a ruler.
Take the measure of the radius and multiply by 2. Any other indirect way of getting the radius does not constitute a measure but a calculation.
The diameter of a circle enters in two formulas.
Length of Circumference: C=Pi*D (D diameter) ====>D=C/Pi
Area of the disk A=Pi *D^2/4 =====>D=SQRT(4*A/Pi), SQRT is the square root operation.

The circumference of a circle is C=2 * pi * r or C= pi * d.

What do we know? C=47.1 and pi.

What are we trying to calculate? d

Put what we know in the equation and solve for d.

47.1 = pi * d

To isolate d, we have to divide both sides by pi.

47.1
------ = d
pi

I get 14.99' or approximately 15' as the diameter.

Good luck,
Paul

what class are you in? Is this your home work? Anyway, You should know that
Circumference = 2 x pie x radius therefore radius - circumference / 2 x pie in this case radius = 30 x 7 / 2 x 22 = 210 / 44 Now you can calculate that fraction.