Controling a construction or not?

the altitude lines of a triangle

option 1: "Draw the 3 of a triangle. What do you see?"

construction steps

Follow the steps:
stap 1   Toolbar ImageSelect the Polygon tool and clik 3 times in the graph to create the vertexes A, B and C. Click again on the first point A to close the triangle.
stap 2Toolbar ImageSelect the Perpendicular tool. Click on the vertex A and the segment [BC].
stap 3Select the Perpendicular tool. Click on the vertex B and the segment [AC].
stap 4Select the Perpendicular tool. Click on the vertex C and the segment [AB].
What do you see?

ready made construction with navigation bar

You can make the construction by yourself the steps are shown by clicking on the navigation bar. This is an option for students at home to provide them a construction that's correct to overview the steps again at home.