The following three coordinates are vertices of a regular tetrahedron circumscribed by the earth (assume spherical). The answer is at the fourth.
P1: S 17.6829061279° E 175.937938962°
P2: N 26.7978332041° E 072.5860786255°
P3: S 52.1980005058° W 015.0157003564°
Anyone know how to solve this?