The last chapter of the Disquisitiones of Gauss

This exposition reviews what exactly Gauss asserted and what did he prove in the last chapter of Disquisitiones Arithmeticae about dividing the circle into a given number of equal parts. In other words, what did Gauss claim and actually prove concerning the roots of unity and the construction of a regular polygon with a given number of sides. Some history of Gauss’s solution is briefly recalled, and in particular many relevant classical references are provided which we believe deserve to be better known