In the figure below, the side length of the octagon is 4 cm. What is the length of the diagonal shown? Express your answer in simplest radical form.

*Solution to yesterday’s problem:*

We can imagine a diagonal going across the square which also serves as a diameter of the circle. The diagonal would split the square into two right triangles, and we could find the length of the diagonal using the Pythagorean Theorem.

(after simplification)

You may recognize this as a 45-45-90 triangle, in which case you didn’t have to do all that work. Anyway, if the diagonal/diameter is inches, then the radius will be half that, or inches.

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