Ordinate Dimensions
With this method you can calculate the perpendicular distance from an origin point. The origin is identified with the Absolute Origin of axes. Distances along the x- and y-axes to objects to measure are specified using extension lines, with the distances indicated numerically at their ends with text labels.
Set the Origin and click on the points to measure: move the pointer parallel to the X axis to get the Y distance and parallel to the Y to get the X distance. If you change the origin, Ordinate dimensions will be updated automatically.