To Enter a Tentative Point (Manually) to Preview a Data Point

Select the required Snap Mode.
Make the desired tool active.
Position the pointer on the location at which you plan to enter a data point.
Press the Tentative button.
The tentative point coordinates are shown in the status bar. A large crosshair is displayed. The intersection of the lines in the crosshair marks the location of the tentative point. If you snap to an element, the element is highlighted.
With the tentative point location displayed, enter a Data point to accept the location.

Manually Entering a Tentative Point to Preview a Data point and Accepting its Location