afreaginname - 08 August 2012 12:16 PM
m_m_italy - 08 August 2012 10:45 AM
To summarize my question was:
[can you] slide a point along a line inclined?
I think my answer is: no
In hexagon yes, the answer is “no”. 
But in life there are far more serious problems
And here the answer is “yes”. 
But that doesn’t keep geeks like me from trying to have fun with the lesser ones like this, and by using slope intercept, you can CALCULATE where the point should be moved to, and you’ll end up with exactly what you wanted to do by sliding it there.
But instead of sliding it to where it should be, you just enter the calculated XY coordinates and it pops to where it should be.
This is no problem for a single point such as you have here, though admittedly it would be far too much trouble if you had to do it repeatedly.
If you want to try it yourself, the equation for the slope of a line (“m”) is:
m = (y1-y2) / (x1-x2)
Where x1,y1 are the XY coordinates for P2 and x2,y2 are the XY coordinates for P3.
Once the slope is found, then you can find the Y-intercept (“b”) with:
-b=mx-y
Where “x” and “y” are the XY coordinates of either P2 or P3. Note that “-b” is the negative value, so for “b” you need to flip the sign.
And finally you can find the Y coordinate for the point you want to move by using the slope intercept equation:
y=mx+b
Where “x” is the X coordinate of P1, and “b” is the Y-intercept from the last calculation
So finally, the coordinates you want to move the “sliding point” to are:
xfinal,yfinal
Where “xfinal” is the X coordinate of P1, and “yfinal” is the slope intercept from the last calculation.
So you would select the point you want to move, type in the xfinal and yfinal values from the last calculation, hit enter, and the point “pops” to exactly where you would have put it if you were able to “slide” it. - which is EXACTLY on the line between P2 and P3, and 90 degrees from P1.
For most people this stuff is boring and a real PITA, but for people like me it’s more fun than a crossword puzzle.
Hell, for most people, just READING about this stuff is boring and a real PITA! 
She is a genius.
Thank you.
But the discomfort remained intact…...
Devo tradurre bene.
Ciao
