If a circle has 18 in what would the area be

If r = 18, the area of the circle is 1017.88

If d = 18, the area of the circle is 254.47

Step-by-step explanation:

Because your question was a little vague I had to give two answers. You need to specify what 18 is; is it the radius or the diameter?

Since the equation for finding the area of a circle is A = 2 * π * r, and half of the diameter of a circle is equal to the radius, the answers will be quite different.

If radius:

r = 18

A = 2 * π * (18)

A = 1017.88

If diameter:

d=18

1/2 * 18 = 9

A = 2 * π * (9)

A = 254.47

what is the original number? you forgot to add it.