Brenda bought 2 and one-half dozen donuts for 8.10. What was the cost per donut

I came up with $3.20 each donut cost.

The area of the circle is  36π mm²

A circle can be described as a round figure whose circumference (the distance round the circle) is equidistant from the centre. An image of a circle is attached.

The area of a circle = πr²

π= pi = 22/7

r = radius = 6mm

The radius of a circle is the distance from the centre of the circle to any point on the circle's circumference.

Area of the circle = π x 6² = 36π mm²

To earn more about the area of a circle, please check: link