The area of a circle is given as:
[tex]A=\pi r^2[/tex]where r is the radius of the circle. In this case the radius is 1 mm (the radius is half the diameter). Then the area is:
[tex]A=\pi(1)^2=\pi[/tex]Therefore:
Exact value:
[tex]\pi[/tex]Appoximate value:
[tex]3.14[/tex]