def angle_diff (a1, a2)
  diff = (a2 - a1) % 360
  diff -= 360 if diff > +180
  diff
end

rows = [{20, 45}, {-45, 45}, {-85, 90}, {-95, 90}, {-45, 125}, {-45, 145},
        {29.4803, -88.6381}, {-78.3251, -159.036},
        {-70099.74233810938, 29840.67437876723},
        {-165313.6666297357, 33693.9894517456},
        {1174.8380510598456, -154146.66490124757},
        {60175.77306795546, 42213.07192354373}].each do |b1, b2|
  puts "Angle difference between %12.4f and %12.4f is %9.4f°" % { b1, b2, angle_diff(b1, b2) }
end