Adobe Illustrator CC Classroom in a Book (2019 Release), First Edition

With the Selection tool ( ) selected, move the pointer over the guide, and click to select it.

Look in the Properties panel on the right to see the Y value. Right now, because you moved the
ruler origin (0,0), the Y shows the vertical distance from the bottom of the artboard. Change
the Y value to –1.75 (inches), and press Return or Enter.