The circumference of a circle is equal to Pi π times the diameter d.
Since the diameter d is equal to 2 times the radius r, the formula for circumference using radius is 2πr.
Substitute the value of the radius r=4.5 into the formula for the area of a circle. Pi π is approximately equal to 3.14.
Multiply 4.5 by 2.
Multiply 9 by π.
Find the Circumference circle (4.5)