 Using the dividers and the 20m scale, the navigator can measure out 120 miles with his dividers.Then setting one end at the top left corner ("A"), he lays out the dividers along the ESE ray (= two quarter-winds below the East ray, or horizontal top of the grid) and marks the spot (point "B" on the diagram).Then using a straightedge ruler draws a line up to the East ray, and marks the corresponding spot "C".