Answer: 22 millimeters
Explanation:
The radius is the line that connects any part of the circle to its center, while a diameter is the line that cut into two equal halves the circle while passing through the centre.
Thus, Diameter is twice a radius
So, if radius of the circle is 11 millimeters.
Diameter = 2 x radius
= 2 x 11 millimeters
= 22 millimeters