Start with a clear, empty graph. draw a line segment from the origin to the point (0,10) on the y-axis. the distance to this point should be 10 (or very close to 10). mark the point (0,10). now leaving the point at the origin fixed, move the other end of the segment around to any other point that's a distance of 10 from the origin. mark the point. keep doing this until you have plotted at least 10 different points that are all 10 units away from the origin. what do you notice?