Respuesta :

Radius = 11 / 2 = 5.5

A = π * 5.5 * 5.5

A = 30.25 π 

3025 / 100 π mm^2

The radius of the circle is half its diameter.
.. r = d/2
.. r = (11 mm)/2 = (11/2) mm

The area is given by
.. A = π*r^2
.. = π(11/2 mm)^2

.. A = (121/4)π mm^2