Nobody knows because we have to know both start and end and you gave only the end point.
To determine the length of a line segment, you need to know the coordinates of both endpoints. In this case, you have one endpoint at (2,1). However, you haven't provided the coordinates of the other endpoint, so I cannot determine the length of the line segment without that information. Please provide the coordinates of the other endpoint, and I will gladly help you find the length.
