def PolygonArea(corners):
    n = len(corners) # of corners
    area = 0.0
    for i in range(n):
        j = (i + 1) % n
        area += corners[i][0] * corners[j][1]
        area -= corners[j][0] * corners[i][1]
    area = abs(area) / 2.0
    return area

# examples
#-50:50 -26.36:50 40.23:15.18 -5.6:-50 -50:-50
corners = [ (-26.36, 50),  (-50, 50),(40.23, 15.18),  (40.23, 15.18), (-50, -50), (-5.6, -50)]
print(PolygonArea(corners))