Final answer:
A graphic artist would measure 2 inches from the top of the canvas and use a tool to create a 2-inch-thick dotted green line at that specific distance.
Step-by-step explanation:
The question pertains to the creation of a horizontal 2-inch-thick dotted green line on a canvas in a graphic arts context. To achieve a line that is exactly 2 inches away from the top of the canvas, the graphic artist would use a ruler or digital tool to measure the distance from the top. The artist would also need to select a tool that allows the creation of a dotted line pattern and adjust the line's color to green. The thickness of the line must be set to 2 inches. If working digitally, software like Adobe Photoshop or Illustrator can be used to create such a line with precision using the line tool combined with stroke options.