Get the Radius which is 8 then multiply (8)(8) and then get 64, finally you need to do 64*3.14 to get the final answer of 200.96. Then you need to divide that by two which would give you the final answer of 100.48
You can round 976 to 1000 and 522 to 500. So it would be 1000 - 500 = 500. The answer you would get after subtracting 976-522 would be more than 400 if you round it.