I'm not sure if this is totally correct, but see if this would work. I've
done this using x,y pairs, with the perpendicular point given last (ie B
(-1,8)). There may be a more efficient equation.
Sub Testit()
Dim v
v = PerpPoint(-6, -4, 13, -2, -1, 8)
Range("A1:B1") = v
'or
Debug.Print "x: "; v(0)
Debug.Print "y: "; v(1)
End Sub
Function PerpPoint(a, b, c, d, e, f) As Variant
Dim x As Double
Dim y As Double
Dim t As Double
x = (b^2*c+a^2*e+a*b*(f-d)-b*c*(d+f)+a*(d^2-2*c*e-d*f)+c*(c*e+d*f))
y = ((a-c)*(d*(a-e)+b*(e-c))+(b-d)^2*f)
t = (a-c)^2+(b-d)^2
PerpPoint = Array(x / t, y / t)
End Function
Returns:
x: 0.194520547945205
y: -3.34794520547945
HTH :)
--
Dana DeLouis
Win XP & Office 2003
"TOMSQUAD" wrote in message
...
Thanks for the advice, this isn't quite what I was looking for, it didn't
work in my case, and I am still stuck. I think it is possibly the = sign
in
the equation that excel isn't reading. Or maybe it is the variables.
"Jason Morin" wrote:
Here's one way you can solve it in Excel:
http://tinyurl.com/45kpx
HTH
Jason
Atlanta, GA
-----Original Message-----
If you have a triangle with the following points
A (-6,-4)
B (-1,8)
C (13,-2)
Find the point perpendicular to AC.
y-y1=m(x-x1)
For this equation, it is solved
y+4=2/19(x+6)
y=2/19x-64/19
y-8=-19/2(x+1)
y=-19/2x-3/2
Therefo
2/19x-64/19=-19/2x-3/2
365x=71
x=.195
..195 is substituted back into the orginal formula to
find for y.
I know to use the x and y variable to have the function
call out a cell with
either the x or y in that cell, what I believe is
screwing up the function is
the = sign in the middle of it. Any suggestions?
.