KnowraConstructible numberLinked fromLinked fromThe 9 pages that link to Constructible number, each with the reason it gives.All 9Broader topic 1Related 5Narrower topic 2Compared with 1Geometric constructionRelated: Coordinates of classically constructible points are constructible numbers.Angle trisectionRelated: Trisecting an angle requires constructing a particular cosine that is not always constructible.Doubling the cubeNarrower topic: The required length is not constructible by these allowed operations.Squaring the circleRelated: Straightedge-and-compass lengths correspond to constructible numbers.Straightedge and compass constructionBroader topic: Coordinates of constructible points have precisely this algebraic form.Solvability by radicalsCompared with: Geometric constructibility allows only a narrower class of extensions than general radical solvability.Gauss–Wantzel theoremNarrower topic: Polygon construction reduces to whether its coordinates or trigonometric values are constructible numbers.Mohr–Mascheroni theoremRelated: This algebraic description characterizes the lengths involved in classical constructions.Niven's theoremRelated: Special rational-angle values often arise in compass-and-straightedge geometry, where exact-value questions meet algebra.