Education Technology

Equation of a Circle

Activity Overview

The aim of this investigation is to develop the equation of a circle of radius, r, centred at the origin, and to explore how the equation changes when the centre is translated parallel to the x and y axes.


ACMNA267 - Describe, interpret and sketch parabolas, hyperbolas, circles and exponential functions and their transformations


  • Circle
  • Equation
  • Translation
  • Dilation

About the Lesson

In this activity, students explore the general equation of a circle with centre (h, k) and radius r. For the first part of the activity, students adjust the radius of the circle and drag a point around the circle to capture the coordinates. In the second part of the activity, students translate the circle using sliders for h and k to view how the equation changes.