In that case, it is definitely possible.
70S is around 5990 km below the equator and 80N is around 6280km above it.
If the 70S point is 6370km away from the equator and 5990km below it, then it must be √(6370² - 5990²) = 2167km to the left of the middle point.
Similarly, if the 80N point is 6370km away from the equator and 6280km above it, then it must be √(6370² - 6280²) = 1067km away from it.
Therefore, the 80N and 70S points are 5990 + 6280 = 12270km away from each other by latitude and 2167 - 1067 = 1100km away by longitude.
That means that they are √(12270² + 1100²) ≈ 12320km away from each other.