Thread: Finding a point distance n between two points.

1. Finding a point distance n between two points.

It's been years since I've had to use algebra and this problem is driving me crazy.

I have point A(5651,4768) and point B(5649,4742).

I want to find a point C(x,y) that is distance 15 from point A, along the line AC.

I've sort of figured it out, but I don't know how to express Cx=?? and Cy=?? in equation form.

2. Originally Posted by ccsutton
It's been years since I've had to use algebra and this problem is driving me crazy.

I have point A(5651,4768) and point B(5649,4742).

I want to find a point C(x,y) that is distance 15 from point A, along the line AC.

I've sort of figured it out, but I don't know how to express Cx=?? and Cy=?? in equation form.
By the distance formula, we want

$15 = \sqrt{(x - 5651)^2 + (y - 4768)^2}$

Find the equation of the line connecting points A and B in terms of x, and then replace y with that expression in the above formula. Solve for x and you are on your way