One circular table has a diameter of 9 ft, and another circular table has a diameter of 20 ft. how much greater is the area of the larger table? round to the nearest whole number

It is best to solve for the areas of two circles and solve for their difference. The area is calculated by the equation, A = πd² / 4
                                   A1 = π x(9 ft)² / 4 = 81π/4 ft²
                                   A2 = π x(20 ft)² / 4 = 100π ft² 
The difference in their values is approximately 250.52 ft².