Divide the diameter by 2 to get the radius. Square the radius and multiply by . Leave your answer in terms of for an exact answer, or use a convenient approximation of to calculate a numeric approximation of the desired area. If you do a numeric approximation, round your answer to the nearest whole square measurement unit. The results of calculations based on measurements must never be reported to a greater precision than the least precise given measurement. Your diameter is measured to the nearest whole unit, so you must report to the nearest whole square unit.
My calculator said it, I believe it, that settles it