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The author is trying to prove it is impossible to square a circle of radius $1$ under the assumption that $\pi$ is transcendental. Even with this assumption, the author explains that if the circle can be squared, then we could draw a line with distance $\pi^{1/2}$. Everything good at the moment. Then he claims that, if such construction is possible, we could also draw a line of distance $\pi$, and that the proof would, under the stated assumption, be complete.

The thing I don't get is how, from a line with distance $\pi^{1/2}$, we could create a line with distance $\pi$.

Sam
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    Not following. Were $\pi$ constructible (a special case of algebraic) then it would be possible to square your circle, not impossible. As to your construction question, if $x,y$ are constructible then so is $xy$. See, e.g., this – lulu Nov 08 '17 at 00:59
  • Once a segment has been chosen that defines the distance $1$ in the plane, we have short constructions for addition, subtraction, multiplication and division of segment lengths; we also have squaring and square root. – Will Jagy Nov 08 '17 at 01:04
  • @lulu. I made a big typo. $/pi$ is assumed to be transcendental*. – Sam Nov 08 '17 at 02:31

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Blue
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