B7. The orthocentre
Draw the orthocentre of a triangle
The orthocentre is the intersection point of the three heights of a triangle. In the acute triangles it is an inner point, in the right triangles it is the vertex of the right angle and in the obtuse triangles it is an outer point. It is usually called "H". You can use the tools, but the explanation will be with commands to learn how to use Input Bar. After typing a command into the Input Bar, you have to press the "Enter ↩" key.
1st Type the heightA=PerpendicularLine(A,a) command.
2nd Type the heightB=PerpendicularLine(B,b) command.
3rd Type the heightC=PerpendicularLine(C,c) command.
4th. Type the H=Intersect(heightA,heightB) command.
Activate the "Move" tool 
and move the vertices in order to verify that the orthocentre travels from inside to outside of the triangle depending on the type.
The two curved arrows located in the upper right corner of the Graphics View allow you to reset the activity.
If the activity is correct, you will get 10 points automatically.
and move the vertices in order to verify that the orthocentre travels from inside to outside of the triangle depending on the type.
The two curved arrows located in the upper right corner of the Graphics View allow you to reset the activity.
If the activity is correct, you will get 10 points automatically.