Math CentralQuandaries & Queries


Subject: Radius of and Inscribed Circle
Name: Anna
Who are you: Student

If I know that the sides of my octagon are 8 units, how do I determine the radius of an inscribed circle?

Hi Anna,


By the symmetry a line segment from the centre of the circle to the midpoint of a side of the octagon is a radius of the circle. Hence the diameter of the inscribed circle is the width of octagon. If you know the side lengths of a regular octagon then the diameter can be found using the method that I used in the answer to a previous question.


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