First the diameter is 5mm so divide that by 2 which is 2.5 and change that to 2.5^{2} times that by pie which is 19.625. Putting that off to the side now you want to find the shaded area... 5 times 5 equals 25. When you are all done with that now you want to subtract them... 25-19.625 equals 5.375... round it 5.4mm2
