Hello guys, I got the following problem...

Code:

In the mid-west many farmers irrigate from a well near
the center of a piece of land using a circular
irrigation system. The farmer plans on farming an
almost square (but it is a rectangle) piece of
property and needs to know some answers for planning.
This program is to get two measurements for a rectangular
piece of property. The measurements will be in feet,
and should be identified with variables named length
width. The program is to calculate the area in square
feet of the rectangle and the largest circle that could
fit into the rectangle.
The farmer wants to know the acreage of:
1. the property
2. the farmable area
3. the non-farmable area

I have like no idea how to put that in an equation. The rectangular piece is easy.. sidea*sideb .Then I'm gonna get the rectangular piece.

But how do I get a equation for how many circles would fit into that rectangular piece? The non-farmable area would just be rectangular piece area - circle. I assume the circle would be the farmable area since it gets watered. And the property would be the rectangular piece.