5. Marking a Point at an Intersection

When marking a point at an apparent intersection of more than two objects, it is necessary to pay close attention to the way the software "highlights" the objects. Make sure that ONLY objects in question are highlighted before marking the point.

Tutorial - Point at an Intersection

Mark a point at the intersection of the lines m and n. Note how objects become highlighted as you approach the intersection and move the cursor around it. Make sure that the point you mark does not belong to the circle.
"Well Done" messsage window will show if you mark the point correctly.

If no "Well Done" feedback is not available (Cabri, GSP, ...) you may verify your construction by manipulating (moving) appropriate objects. (See chapter 3 of this tutorial).

In this example, try moving the following objects and observe results:

(1) Grab the line n (move the cursor over to highlight it and right-click) and move it up and down (while holding right mouse button, move the cursor up and down). If your construction is valid, the intersection moves along the lines m and n.

(2) Grab the circle c and move it. The intersection should not move.


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