I am pretty sure it is 65.48535.
First we need to find the area of the circle. If the diameter is 4.3, the radius would be 2.15. 2.15 to the power of 2 is 4.6225. That times pi is 14.51465.
So now we need to find the area of the rectangle which obviously is 80. Now we subtract the area of the circle. 80 - 14.51465 = 65.48535.
Our answer is 65.48535