A (3/-1/2), B (0/3/4), C (5/5/6) und D(8/1/4)
AB = [0,3,4] - [3,-1,2] = [-3, 4, 2]
AC = [5,5,6] - [3,-1,2] = [2, 6, 4]
AD = [8,1,4] - [3,-1,2] = [5, 2, 2]
A = 1/2 * (|AB ⨯ AC| + |AD ⨯ AC|) = 1/2 * (|[-3, 4, 2] ⨯ [2, 6, 4]| + |[5, 2, 2] ⨯ [2, 6, 4]|) = 2·√237 = 30.79