Constructing the Orthocenter

Date: 01/27/99 at 17:43:51
From: Justin
Subject: Orthocenter

I need the steps for how to construct it!

Date: 01/28/99 at 09:40:51
From: Doctor Floor
Subject: Re: Orthocenter

Hi Justin,

Thanks for your question. I suppose you want to know how to construct 
the orthocenter of a triangle using just ruler and straightedge. 

To construct the orthocenter you should construct two (three are not 
necessary) altitudes in a triangle. Their intersection is the 
orthocenter. 

You can construct an altitude in a triangle like this:

      

More basic constructions can be found in the Dr. Math archives:

  http://mathforum.org/dr.math/problems/zaidi11.13.98.html   

I hope this helps!

Best regards,
- Doctor Floor, The Math Forum
  http://mathforum.org/dr.math/