Example applications
Set the measuring tool in a corner of the room and position it so that the 0° laser line runs parallel to the reference line (e.g. wall). Measure the distance between the laser line and the reference line directly next to the measuring tool and again as far as possible from the measuring tool. Align the measuring tool so that both distances are equal.
Then, from at least two different points, measure the distances between the 90° laser line and the wall. If the distances to the 90° laser line are equal, the walls are at right angles.