# Thread: Find a Cartesian co-ord when you have a start co-ord, distance and angle

1. ## Find a Cartesian co-ord when you have a start co-ord, distance and angle

Hi guys,

I am trying to determine a co-ordinate, when I have a start co-ordinate, a distance to the new co-ordinate and the angle. (using a 2D Cartesian system).

I believe the answer is something like the following; however it does not seem to give me the right answer.

x2 = x1 + cos(angle) * distance
y2 = y1 + sin(angle) * distance

any help will be greatly appreciated!

Thanks, Mike

2. arctan(y/x)=angle

if the start co-ordinate is (x1,y1) then distance =sqrt((x1-x)^2+(y1-y)^2)

3. Thanks poirot

Though I do not think I explained what I need fully.

I have the following:

1) a start co-ord x1,y1
2) distance to new co-ord (x2,y2)
3) angle/direction to new co-ord (x2,y2)

and I need to work out the what the new co-ordinate (x2,y2) will be.

Any takers? thanks

4. I have explained. I have used (x,y) as the new co-ordinates. You have 2 equations involving x and y. Solve

5. Originally Posted by mxdatamike
I am trying to determine a co-ordinate, when I have a start co-ordinate, a distance to the new co-ordinate and the angle. (using a 2D Cartesian system).
x2 = x1 + cos(angle) * distance
y2 = y1 + sin(angle) * distance
It is not at all clear what transformation you have described.
Are you rotating about a point, which point?
Then are you elongating the vector?
What do you think multiplying the cosine by the distance does?

I think that you should try giving a detailed description of the transformation.