Petrie notes variations from mean axis of 26º 2' 30" altitude for the ascending passageway.
<[www.ronaldbirdsall.com]; #39
Variations from mean axis of 26º16'40" altitude of the Grand Gallery
<[www.ronaldbirdsall.com]; #45
57 3/11 will suffice for both, 57 3/11 digits width between the ramps on the grand gallery floor. 57 3/11 / 28 = 45/22 the run-rise of a seked of 3 19/45 which supports the angle of the ascending passage angle of 26º 3' 12.58 seconds as noted in the original survey by Charles Piazzi Smyth, but does not discount what Petrie proposed.
By using the Mathematics of Ancient Egypt is the area of a square with a radius of 7 and a circumference of 176 as generated by G1's exterior dimensions. 7^2 * 22/7 = 154...154/45 = 45/22...(22/45 / 100/99 = 40/81) the 3 37/81 seked of the Grand Gallery. I would not challenge Petrie's measured angles of 26º 16' 40” knowing the following is the likely figure based on the narrowly defined parameters of the cubit. Where (280/81) / (45/22) = 1232/729 =(2^4×7×11)/(3^6) which can be explained by the use of pi in the Ancient Egyptian ratio of (8/9)d^2 and provides a reason for its use. If Smyth is correct, then this junction between the ascending passageway and Grand Gallery mathematically marks the transition from 2d circular geometry to 3d spherical geometry.
360 / 7 / 4 / 44/7 = 2 1/22 (45/22) gives the seked of 3 19/45 for ascending passage. (Smyth) there is a slightly different figure for the Grand Gallery floor which Smyth notes and the angle that transitions into what can be calculated as a seked of 3 37/81 (280/81) with a rise-run of 40/81 = 26º 16' 53.08” which is well within Petrie's margin of error. You can if you wish take it as one continuous run of 26º 16' 53.08”, but I have too much evidence to the contrary to support that perspective.

Regards,
jb