Geometric Construction of the Square Roots of a Complex Number
This Demonstration shows a geometric construction of the square roots and of a complex number . The square roots lie on the angle bisector of the argument of and on a circle through the origin of radius , which is the geometric mean of and . The complex number can be selected using the locator.
 D. Kurepa, Higher Algebra, Book 1 (in Croatian), Zagreb: Skolska knjiga, 1965 p. 108.