Question 1025322
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1.  The area of the remaining octagonal shape is

    {{{9^2}}} - {{{4*((3*3)/2)}}} = 81 - 2*9 = 63 sq.units against {{{pi*4.5^2}}} = 63.585 sq. inits.



2.  The perimeter of the remaining octagonal shape is

    {{{4*3 + 4*(3*sqrt(2))}}} = {{{12 + 12*sqrt(2)}}} = 28.971 units.


    The ratio of the perimeter of the remaining octagonal shape to the diameter of the circle is 

    {{{28.971/9}}} = 3.219  (approximately).

    The difference between this value and {{{pi}}} is 0.077 (approximately).
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