Answer:
4
kind of confusing question
Graph 1: Domain = 2 <= x < 12
Graph 1: Range = {2,4}
Graph 2: Domain = 3 <= x <= 10
Graph 2: Range = -6 <= y <= 4
Graph 3: Domain = 4 < x < 11
Graph 4: Range = -6 <= y < 2

We know that
.
Solve using cross multiplication of the last two fractions. I will use
to represent the width of the rectangle. 
Multiply. 
Divide both sides of the equation by
. 
Ok so we know that the distance around the circle (or circumference) is equal to the diameter times pi.
This means that

d being the diameter,
This means that:

= 12.00028271
= 12 m
So the diameter of the circle is 12 metres.
Hope this helped
About 3.40 rounded to the tenths place