The area of a circle is:
[tex]A=\pi\cdot r^2[/tex]
As you have the diameter, use it to find the radius: the radius of a circle is equal to the half of the diameter:
[tex]\begin{gathered} r=\frac{d}{2} \\ \\ r=\frac{17.91\operatorname{mm}}{2}=8.955\operatorname{mm} \end{gathered}[/tex]Then, the area is: 251.80 millimeters[tex]\begin{gathered} A=(3.14)(8.955mm)^2 \\ A=251.80\operatorname{mm} \end{gathered}[/tex]
