1. Determine the direction of the internal shear force V.

2. Slice through the cross section at the point of interest in a direction perpendicular to the direction of the internal shear force V.

3. The Q section property is based on a free-body diagram of a portion of the cross section. The appropriate portion of the cross section begins at the slice and extends in a direction perpendicular to and away from the neutral axis.

4. Q is the moment of this area about the neutral axis.
(The moment of an area is found by multiplying the area times the perpendicular distance between the area's centroid and the neutral axis for the entire shape.)

5. It may be helpful to break the overall area needed for Q into several smaller rectangular areas.