The faces of the pyramid are formed by constructing a geometric line from the north and south ends of the base line to the upper turning point on the principal ellipse. These faces are highlighted in the drawing, and their object property boxes are also displayed showing the angle of the faces in degree-minute-second format for ease of comparison to Petrie's survey data, which is shown below.
Petrie's measurements of the face angles of the pyramid contain several large errors and assumptions, some of which are a result of him incorrectly identifying the shaft exit points on the pyramid's faces. Other possible errors he recognised himself, and he gave no weighting to those results in his work. Consequently the angles he reports for the faces can only be considered as good general approximations, and are:
The angles of the geometric face lines on the interactive drawing are close to the measurement that Petrie reports for the northern face, and have a substantial difference to the angle he determined for the south face. If you zoom in on the apex of the pyramid you can see that because these geometric face lines are symmetrical about the vertical axis, this zoomed-in drawing shows how the pyramid's stonework rises to an apex that is offset to the south of vertical center line of the building.
This discrepancy between the symmetrical geometric faces and the asymmetric stonework is resolved later in this work.