Triangle ABC has the vertices (1,2), (3,5), and (6,3) Find the coordinates of the orthocenter.
We only need the equations of two lines to do this
Find the slope between AB = (1,2) and (3,5) = (5-2) /( 3 -1) = 3/2
The equation of the line perpendicular to segment AB through ( 6,3) is
y = (-2/3)(x - 6) + 3
y = (-2/3)x + 4 + 3
y = (-2/3)x + 7 (1)
Next
Find the slope between AC = ( 1,2) and (6,3) = (3 -2) /( 6 - 1) = 1/5
The equation of the line perpendicular to segment AC through B is
y = -5 ( x -3)+ 5
y = -5x + 20 (2)
Find the x coordinate of the orthocenter by setting (1) = (2)
(-2/3)x + 7 = - 5x + 20 multiply through by 3
-2x + 21 = -15x + 60
13x = 39
x = 3
And the y coordinate is -5(3) + 20 = 5
So....the orthocenter is actually B = (3,5)