 In this zetetic stage of analysis, the geometrical problem is transformed into the algebraic problem of solving a standard-form cubic equation (i.e., a cubic equation that does not include a quadratic term). However, for Viète, the genuine solution to the problem must be supplied in the stage of exegetics, which offers the geometrical construction and thus the synthesis, or  proof.[3]  And it is here that the neusis postulate supplies the guarantee that such a solution can be found: By assuming the neusis problem solved, we can construct the curve that satisfies the two cubic equations above (i.e., we can construct the roots of the equations) and thereby construct the sought after mean proportionals. In other words, there was an assumed equivalence in Viète’s program between solving an algebraic problem that required identifying the roots of specified cubic equations and solving a geometrical problem that required the construction of a curve. We also see this in his treatment of trisecting an angle: To solve the angle-trisection problem is to solve two standard-form cubic equations, which Viète reveals in his algebraic elaboration of the geometrical problem (cf. Bos 2001, 173–176). In fact, assuming the neusis postulate, we can solve any standard-form cubic equation, and since it was already known at the time that all fourth-degree equations are reducible to standard-form cubic equations, what Viète supplied with his marriage of algebra and geometry in his 1594 Supplement was a program that solved all line-like problems that could be elaborated in terms of cubic and quartic equations.