A residual<span> is the difference between the observed y-value (from </span>scatter plot<span>) and the predicted y-value (from regression </span>equation<span> line). It is the vertical distance from the actual </span>plotted<span> point to the point on the regression line. </span> Have a nice day kid!
It is ten units, as the two sides are of 6 and 8 so you must square them both, add them together (which gives you 100) and then square root that, which gives you 10