Number
51.84°, or 7.2 squared
The Great Pyramid’s faces rise at about 51°50′. In decimal degrees that is 51.84, and 7.2 × 7.2 = 51.84. Grant builds a chain from here to 72, precession, and 432.
Emőke Dénes, “The Great Pyramid of Giza”, CC BY-SA 4.0, via Wikimedia Commons
The arithmetic is true and the measurement is Petrie’s, from 1880 to 1882. Egyptologists explain the angle with the seked, the Egyptian measure of slope: a rise of one cubit for a run of 5½ palms, which gives arctan(7 ÷ 5.5) = 51.84°. The same number, reached from a builder’s rule rather than a hidden code. The two explanations are not rivals about the angle. They are rivals about what the angle means.