Parallel and Perpendicular Lines in the Coordinate Plane: Exact Slope Triangles

① This GeoGebra template demonstrates the slope relationships of parallel and perpendicular lines in the coordinate plane, using exact slope triangles to visualize the geometric meaning of slope. ② Core math concepts include slope of a line, equal slopes for parallel lines, negative reciprocal slopes for perpendicular lines (product = -1), and construction of slope triangles. ③ Construction uses commands such as Line, Slope, Circle, Intersect, Ray, Numerator, Denominator, Point, Polygon, Segment, with objects like lines f, a, c, d, points A through M, polygons t1, h_1, and a button (button1) to toggle display. ④ Suitable for upper middle school or high school coordinate geometry lessons, enabling students to explore how slopes change under parallelism and perpendicularity, and to connect visual patterns with algebraic rules.