Problem with some math

[Atoa]

I having some problems with math in rgss.

It's a bit hard to explain, so i will use this example:

the red dot is sprite 1, and the blue dot is the sprite 2. I want to set the purple dot (sprite 3) alingned with them. at a set distance from sprite 2 (the dark green line).

I have sprite 1 x/y postion, sprite 2 x/y position and the distance.

Any help about how i can get sprite 3 x/y position?

 

[Star]

Here's an example, not sure how to make a formula

Sprite 1 - x = 10
Sprite 1 - y = 15
Sprite 2 - x = 20
Sprite 2 - y = 30

Sprite 2x - Sprite 1x = 10
Sprite 2y - Sprite 2y = 15

Now find the relation between their distance with the Red and Blue dot

The distance between the red and blue dot is 100% now find the percentage of the blue and purple dot. If the distance is 200ft for the red and blue dot and the distance for blue and purple dot is 50ft take 200 and divide it by 50 to get 4 then use this formula 4 * x = 100 or x = 100/4 to get your percentage which in this case is 25%
if the distance between the blue dot and purple dot is 50% multiply the x10 and y15 by .5 or 50% to get x5 and y7.5 and add them to sprite 2 x and y to get sprite 3 x 25 y 37.5.
if the distance between the blue dot and purple dot is 150% multiply the x10 and y15 by 1.5 or 150% to get x15 and y22.5 and add them to sprite 2 x and y to get sprite 3 x 35 y 52.5.

 

[Atoa]

@Star
Thanks for the help. with other info i've got i think i can handle this now ^^