← etc / Encyclopedia of Triangle Centers

X₁₅₉¶

X₉-OF-TANGENTIAL-TRIANGLE

X₁₅₉ = X₉-of-tangential triangle if ABC is acute

X₁₅₉ (X₉-OF-TANGENTIAL-TRIANGLE) constructed on acute reference triangle \((a, b, c) = (5, 6, 7)\) with unit baseline AB = \(1\).¶

"""GEOMETOR construction model for X_159 = X_9-OF-TANGENTIAL-TRIANGLE."""

        from __future__ import annotations

        from pathlib import Path

        import sympy.geometry as spg
        from geometor.model import Model

        from geometor.etc.ops import (
            central_line,
            circumcenter_of,
            construct_baseline_triangle,
            create_model,
            eval_trilinear_point,
            promote_point_to_top,
            symmedian_point_of,
        )
        from geometor.etc.render import write_center_svg


        def construct_x_00159(
            model: Model, A: spg.Point, B: spg.Point, C: spg.Point
        ) -> spg.Point:
            """Construct X_159 = X_9-OF-TANGENTIAL-TRIANGLE on reference triangle ABC."""
            X_159 = eval_trilinear_point(model, A, B, C, '(a*((a**(2) + b**(2) + c**(2))*sin(2*A) + (c**(2) - b**(2) - a**(2))*sin(2*B) + (b**(2) - c**(2) - a**(2))*sin(2*C)))', ID="X_159", classes=["selected", "target"])
            X_6 = symmedian_point_of(model, A, B, C, ID="X_6", classes=["center", "incident"])
            X_25 = eval_trilinear_point(model, A, B, C, 'sin(A)*tan(A)', ID="X_25", classes=["center", "incident"])
            central_line(model, X_6, X_25, 6, 25, incident=True)
            X_3 = circumcenter_of(model, A, B, C, ID="X_3", classes=["center", "incident"])
            X_66 = eval_trilinear_point(model, A, B, C, 'b*c/(b**(4) + c**(4) - a**(4))', ID="X_66", classes=["center", "incident"])
            central_line(model, X_3, X_66, 3, 66, incident=True)
            X_22 = eval_trilinear_point(model, A, B, C, 'a*(b**(4) + c**(4) - a**(4))', ID="X_22", classes=["center", "incident"])
            X_69 = eval_trilinear_point(model, A, B, C, '(cos(A))/a**(2)', ID="X_69", classes=["center", "incident"])
            central_line(model, X_22, X_69, 22, 69, incident=True)
            return promote_point_to_top(model, X_159)


        def build_model(
            sides: tuple[float, float, float] = (5.0, 6.0, 7.0),
            show_guides: bool = False,
        ) -> Model:
            """Build a `geometor.model.Model` for X_159 on the given reference triangle."""
            model = create_model('X_159 = X_9-OF-TANGENTIAL-TRIANGLE')
            A, B, C = construct_baseline_triangle(model, *sides, show_guides=show_guides)
            construct_x_00159(model, A, B, C)
            return model


        if __name__ == "__main__":
            here = Path(__file__).resolve().parent
            model_acute = build_model((5.0, 6.0, 7.0))
            model_acute.save(str(here / "x-00159.json"))
            write_center_svg(
                model_acute,
                here / "x-00159.svg",
                subtitle="(a, b, c) = (5, 6, 7) | AB = 1",
            )
        

X159¶

X₁₅₉¶