r=2.25

The circumference of a circle is equal to Pi π times the diameter d.

π⋅(diameter)

Since the diameter d is equal to 2 times the radius r, the formula for circumference using radius is 2πr.

2π⋅(radius)

Substitute the value of the radius r=2.25 into the formula for the area of a circle. Pi π is approximately equal to 3.14.

2⋅π⋅2.25

Multiply 2.25 by 2.

4.5π

Multiply 4.5 by π.

14.13716694

14.13716694

Find the Circumference circle (2.25)