Question 1191722
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<pre>

This regular octagon has the central angle of {{{360/8}}} = 45 degrees 

and has the side length of 7*2*sin(22.5°) = 7*2*0.3827 = 5.3578 centimeters,


           NOT  4 centimeters.



So, your input information is  WRONG :  it is  INCORRECT.


Such regular octagon as described in your post DOES NOT EXIST and CAN NOT EXIST.
</pre>

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