Squaring the Circle

Classic Problem
Squaring the Circle is creating a square with the same area as that of a given circle.

Solution
The problem of squaring the circle reduces to:


 * starting with a line segment of given length ($1$, say)


 * constructing a line segment of length $\sqrt \pi$ of the first.

Also see

 * Squaring the Circle by Archimedean Spiral
 * Squaring the Circle by Compass and Straightedge Construction is Impossible