Verifying if a point falls into a hough line returned from the houghline function

I have as set of points for which I want to check whether or not they fall inside a hough line.

I have been trying to do this by calculating R, and seeing whether or not in matches the R of the line for every point given the theta.

However, I tried to do this for the start and end points of the hough lines and can't seem to get the correct R result, even though they do fall in the hough line.

So far I've been using the following formula:

rho = y * sind(theta) + x * cosd(theta).

I am using theta as degrees, since that is how I interpret the results, but I might be wrong.

Theta range: [-90, 89]

Rho range: [-700, 700]

Thanks in advance!

[Image Analyst]

Not really enough to go on (no code, etc.) but maybe the FAQ below will help:

Why is 0.3 - 0.2 - 0.1 or similar not equal to zero?