Education Technology

QLD (Nspire): Circumcircles

by Texas Instruments


Students are required to to determine the following:

  • Equation to a straight line given two points.
  • Equation to a straight line given the gradient (perpendicular) and a point.
  • Point of intersection between two or more lines.
  • Equation to a circle given centre and radius


  • Circumcentre
  • Circumcircle
  • Perpendicular bisector
  • Simultaneous equations

About the Lesson

Students start by exploring the geometric properties of a circumcircle and its construction. This information is then applied to points on the Cartesian plane with students determining equations to lines (given two points), equations to lines (given point and gradient), solve simultaneous equations and finally the equation to a circle. Lots of opportunities to extend the concepts covered in this activity.