WSP Simson Line

  • Simson Line

    Grade: High School

    This applet allows for the construction and exploration of the Simson Line.

    This interactive is optimized for your desktop and tablet.


    Release: 2015Q2, Semantic Version: 4.2.0, Build Number: 911.6-r, Build Stamp:


    How to Use

    • Use the red points on the triangle to adjust the size
    • You can drag the triangle around the workspace by dragging its area, but you will not be able to drag any other object.


    • The buttons are meant to be used sequentially, so they will appear in order.
    • The Reset button can be used to start over at any point.



    • Why are P(1), P(2), and P(3) collinear? Can you provide a proof?
    • Find the orthocenter of a triangle along with the Simson Line. Now, connect P to the orthocenter. What is the relationship?

    Objectives and Standards

    NCTM Standards and Expectations
    • Geometry / Measurement
    • Functions and Trigonometry
    • Understand that by similarity, side ratios in right triangles are properties of the angles in the triangle, leading to definitions of trigonometric ratios for acute angles.
    • High School (9-12)
    • Geometry
    • Measurement