If the circumference of a circle is 18 in. how do I find out the area?

Answer 1

circumference = 2 pi r
2 pi r = 18
r = 9/pi


area = pi r^2
= 81 / pi

Answer 2

You were given 2 formulas concerning pi (which is about 3.14)

The circumference of a circle is 2 x pi x radius and the area of a circle is pi x (radius squared)

Using thes two formulas and a little algebra, the answer should be easily found.
Good luck

Answer 3

Area of circle = (pi)r^2

Circumference = (pi)D

D=2r

Plugging 2r into circumference formula you get

Circumference=(pi)2r

Solving for r, you get

r = circumference/[2(pi)]

so if Area = (pi)r^2, then

Area = (pi)(circumference/[2(pi)])^2

= (pi)(circumference)^2/[4(pi)^2]

= circumference^2/[4(pi)]

Since circumference is 18, then area is

18^2/[4(pi)] = 324/[4(pi)]

= 25.8 inches^2

Answer 4

Circunference = 2(pi)R ==> R = circunference/2(pi)

Area = (pi) R^2 = 1.4 sq in for circunference = 18 in

Answer 5

radius={circumference divided by pi(3.1416)}divided by 2
={18/3.1416}/2
=5.73/2
=2.87
area=pi times radius squared
=3.1416 times{2.87*2.87}
=3.1416*8.24
area =25.89in

Answer 6

"3.14 x square of radius" is equal to area of circle

"2 x 3.14x radius" is equal to circumference

I think that you can arrange them and get your result.

Answer 7

pi x r squared

Answer 8

multiply pi by the radius squared, hope i helped!!!!!!!

Answer 9

pie 3.14 times (r) radius 9 squared is ill let you find that one out.

Answer 10

pi r^2

circumfrence = 18
radius = 9
pi * 81
area ~ 254.34