using a graph tool
see the attached figure
Let
D----------> the diameters of the circle O
D=8 in
D=8 in is < 10 in and D=8 in is > 5 in
the center of the circle is the point (0,0)
the circumference of the circle=pi*D-------> 8*pi in
the circumference value estimate is about 24 in
the circumference value using a calculator is ----> 8*pi----> 25.13 in
the difference in the exact value and the estimate value is
25.13-24--> 1.13 in
