Using a Compass
When the compass point is anchored on a fixed location, all the points that fall on the line drawn by the pencil (with the compass placed at a constant, unchanging angle) will be at the same distance away from the fixed location where the point is.
Solving the Question
Therefore, according to the properties of a curve drawn using a compass, all the points on the blue arc are the same distance from point R. We know this because the compass has been anchored to that location.
Answer
same distance from point R