a) 226.865 yd^2
[The formula of finding the area of a circle when you have the diameter is A=1/4πd^2. (π=3.14) Therefore, plugging in the diameter of 17 yards, you get the equation A=1/4(3.14)(17^2). Solve this equation to get the area of the circle: 226.865]
b) 254.34 mm^2
[The formula of finding the area of a circle when you have the diameter is A=1/4πd^2. (π=3.14) Therefore, plugging in the diameter of 18 mm, you get the equation A=1/4(3.14)(18^2). Solve this equation to get the area of the circle: 254.34]
Hope I helped! Have a nice day! :)