Open AlgebraView and GraphicsView under View in Menu.
2.
Make a triangle with the vertices , and by clicking Polygon. Then you need to click on three positions in GraphicsView where you want the vertices of the triangle to be. Finally, complete the triangle by clicking on the point that you started with.
3.
Select PerpendicularLine. Construct the line from vertex perpendicular to the opposite side , construct the line from vertex perpendicular to the opposite side , and construct the line from vertex perpendicular to the opposite side . These lines are the altitudes.
4.
Select Intersect by first clicking tool number 2, then tool number 4 in the drop-down list, and click on two of the altitudes to construct the point of intersection between them. This point is the orthocenter.
. Then you need to click on three positions in 
. Construct the line from vertex perpendicular to the opposite side , construct the line from vertex perpendicular to the opposite side , and construct the line from vertex perpendicular to the opposite side . These lines are the altitudes. 
by first clicking tool number 2, then tool number 4 in the drop-down list, and click on two of the altitudes to construct the point of intersection between them. This point is the orthocenter. 
