Enneagonal antitegum

The enneagonal antitegum or eat, also known as the enneagonal trapezohedron, is an antitegum based on the enneagon, constructed as the dual of an enneagonal antiprism. It has 18 kites as faces, with 2 order–9 and 18 order–3 vertices. .

Each face of this polyhedron is a kite with its longer edges $$\frac{2+4\cos\frac\pi9+\csc\frac{\pi}{18}+\sqrt3\csc\frac\pi9}{2} ≈ 8.29086$$ times the length of its shorter edges.