That would be 1+y≥9
the one and the y go on one side and the nine on the other
The area for a circle with a diameter of 8 cm is 50.24 cm². The area of a circle with a radius of 3 cm is 28.26 cm². 50.24 - 28.26 = 21.98 cm. So the difference is 21.98 cm.