WSP Circumcircle

  • Circumcircle

    Grade: High School

    This applet allows for the construction and exploration of a circumcircle.
    This interactive is optimized for your desktop and tablet.


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


    How to Use

    • Use the red points to adjust the distances between the three points.


    The buttons are meant to be used sequentially.

    • Steps- By clicking on these buttons, you will reveal the next step in the construction.
    • Show Measurements- will reveal the distance of each point to the circumcenter.
    • At any time, you can press the Reset button to start over. 


    Before using any of the buttons, explore the following:

    This interactive shows the location of three cities in relation to one another. Where should a major hospital be built so that it is equidistant to each city?

    At any time, answer the following questions:

    • When does the circumcenter lie outside of the triangle?
    • Why are only two perpendicular bisectors needed to find the circumcenter?
    • Why does this construction work? Create a formal proof.

    Objectives and Standards

    NCTM Standards and Expectations
    • Geometry / Measurement
    • 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