[] , [] , [^] , []Adding feet of perpendiculars to triangle / It is good to explore with freehand.(GC World : Various Problems ,What will occur when something is added?)
Let's draw a triangle.
And let's add perpendiculars from B and C to the respective opposite sides.
Can a similar triangle be made?
Or can you make a similar triangle to ABC based on this figure?

I think that it is good to try this kind of problems on paper.
You may be able to find the answer of the former question even if you only try this only.
On the other hand, it may be difficult to find a similar triangle to ABC by freehand.

Forum of Geometric Constructor by Y.Iijima