I constructed an altitude on an obtuse traingle. How could i check to make sure it was an altitude?

Answer 1

Extend the altitude downwards so that you have a line that is the same length as the altitude. Connect the and of this line segment with the other 2 points of the triangle. If your altitude is correct, this will make a mirror image of your triangle. The two lines that you just drew should be the same length as the mirror image lines of the original triangle. If your altitude isn't right they won't be the same length.