This Excel file has a series of sheets which illustrate the link between the equation of a circle and the corresponding graph. It goes on to deal with the intersection of a circle with a straight line.
The first interactive sheet shows the equation and graph of circles centred on the origin where the radius can be altered. The next two sheets deal with transposing the centre and changing the radius, the changes being shown on a graph and in the equation. The next sheet shows the coordinates of the end points of a diameter for the students to find the equation of the circle.
The penultimate sheet shows four points on a circle. Students can reveal the coordinates of the centre and the radius so that they can find both forms of the equation of the circle. The final sheet expects students to calculate the coordinates of the points of intersection of a circle and a straight line.
Note: This program was designed by be viewed on a screen with a resolution of 1024 x 768. Users may have to adjust the resolution of their screen for the pages to display as was originally intended. The program uses macros which need to be enabled on users’ machine.