r=4
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=4 into the formula for the area of a circle. Pi π is approximately equal to 3.14.
2⋅π⋅4
Multiply 4 by 2.
8π
The result can be shown in multiple forms.
Exact Form:
8π
Decimal Form:
25.13274122…
Find the Circumference circle (4)