How To Find An Orthocentre

[SashaB]

Hi,

I am having trouble finding out how to calculate the orthocentre of atriangle after figuring out the slopes of the two altitudes. Is there a formulathat I need to sub my values in to? I wrote down the answer at the end, but I am not sure as to how they calculated that.
Since my work was hand written, I attached a picture of it.
Thanks for your help!
Sasha

 

[Deleted member 4993]

Hi,

I am having trouble finding out how to calculate the orthocentre of atriangle after figuring out the slopes of the two altitudes. Is there a formulathat I need to sub my values in to? I wrote down the answer at the end, but I am not sure as to how they calculated that.
Since my work was hand written, I attached a picture of it.
Thanks for your help!
Sasha

For a quick review, go to:



http://en.wikipedia.org/wiki/Altitude_(triangle)

 

[Quaid]

Hi Sasha:

In your work, you wrote

0 = 1/7(-2) + b

0 = 1/7(+2) + b

Changing -2 to +2 is a mistake.

Are you sure that you copied the exercise correctly?

As posted, DEF is a right triangle because DF is perpendicular to DE.

The orthocenter for a right triangle lies on the vertex at the right angle, so either the exercise is incorrect or the given answer is.

Cheers