← etc / Encyclopedia of Triangle Centers

X₇₇₄¶

CROSSPOINT OF X₁ AND X₁₅₈

X₇₇₄ is the crosspoint of X₁ and X₁₅₈.

X₇₇₄ (CROSSPOINT OF X₁ AND X₁₅₈) constructed on acute reference triangle \((a, b, c) = (5, 6, 7)\) with unit baseline AB = \(1\).¶

"""GEOMETOR construction model for X_774 = CROSSPOINT OF X_1 AND X_158."""

        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,
            construct_baseline_triangle,
            create_model,
            eval_trilinear_point,
            incenter_of,
            promote_point_to_top,
        )
        from geometor.etc.render import write_center_svg


        def construct_x_00774(
            model: Model, A: spg.Point, B: spg.Point, C: spg.Point
        ) -> spg.Point:
            """Construct X_774 = CROSSPOINT OF X_1 AND X_158 on reference triangle ABC."""
            X_774 = eval_trilinear_point(model, A, B, C, '(cos(B))**(2) + (cos(C))**(2)', ID="X_774", classes=["selected", "target"])
            X_1 = incenter_of(model, A, B, C, ID="X_1", classes=["center", "incident"])
            X_21 = eval_trilinear_point(model, A, B, C, '1/(cos(B) + cos(C))', ID="X_21", classes=["center", "incident"])
            central_line(model, X_1, X_21, 1, 21, incident=True)
            X_55 = eval_trilinear_point(model, A, B, C, 'a*(b + c - a)', ID="X_55", classes=["center", "incident"])
            X_201 = eval_trilinear_point(model, A, B, C, '(cos(A))*(1 + cos(B - C))', ID="X_201", classes=["center", "incident"])
            central_line(model, X_55, X_201, 55, 201, incident=True)
            X_821 = eval_trilinear_point(model, A, B, C, '((sec(A))**(2) /((cos(B))**(2) + (cos(C))**(2)))', ID="X_821", classes=["center", "incident"])
            X_823 = eval_trilinear_point(model, A, B, C, '1/((sec(B))**(2) - (sec(C))**(2))', ID="X_823", classes=["center", "incident"])
            central_line(model, X_821, X_823, 821, 823, incident=True)
            return promote_point_to_top(model, X_774)


        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_774 on the given reference triangle."""
            model = create_model('X_774 = CROSSPOINT OF X_1 AND X_158')
            A, B, C = construct_baseline_triangle(model, *sides, show_guides=show_guides)
            construct_x_00774(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-00774.json"))
            write_center_svg(
                model_acute,
                here / "x-00774.svg",
                subtitle="(a, b, c) = (5, 6, 7) | AB = 1",
            )
        

X774¶

X₇₇₄¶