



 Each example below contains an html file and a CaR file (with extension zir). Click the html file to open it in the browser. You will find a Java applet, which is in fact the corresponding CaR file embedded in the homepage. You can click the CaR file to download it to your hard disk. It can be opened and edited with your installed CaR program.





 Perpendicular Bisectors of Triangle





 Drag A to see the change of D, the intersection of 2 perpendicular bisectors. Use the second icon to track the point D (so that it leaves behind a trace when it is moved): 1. click the 2nd icon 2. click once at D 3. drag A





 A triangle with measurements of 3 sides. Drag any vertex to change its shape. Estimate the sum of 2 sides, compare it with the third. Move on to the next activity (pythagorean inequality) to explore the sum of 2 squares on any 2 sides.





 Compare the sum of squares of any 2 sides with that of the third. Which is greater? Under what condition?





 A triangle is rotated about a given center with a given angle. You can change the shape of the triangle, the angle and center or rotation. Identify corresponding vertices. Identify angles formed with corresponding vertices and the center. Where would be the green triangle if you move the center up? How can you make a parallelogram with the triangles?





 3 pairs of colored lines passing through 4 movable points (A to D). Rearrange the points to make all pairs perpendicular. Can you make only 2 pairs perpendicular? Can you make them perpendicular by moving one vertex only?





 Drag A and see how B moves. Where is B when A is (1,0)? (2,3)? ... How could you put B at (0,1)? (2,0)? ... When will A and B coincide? Use the 2nd icon to track B (and A): 1. click the 2nd icon 2. click once at B (or shift+click once at B and A) 3. drag A The diagram shows both tracks. How are these curves related?





 Reflection about a diagonal line





 Move Q by dragging P. Make Q move along the perimeter of the polygon.





 Reflection about a vertical line





 Similar to the previous activity. Q is tracked once you drag P. In this example, Q is image of P when reflected about a vertical line.





 The colored segments represent the paths when P is drawn to the nearest point on each side. Estimate the position of P which makes the 3 segments equal. Where could it be if at least 2 segments are equal. Investigate the properties of and relations between incentre and angle bisectors.





 This applet contains most of the icons. A triangle is predrawn with all angles and sides shown. User can use the icons to modify the figure and make any investigations about a triangle.






