area of //gram ABCD = |cross-product of vectors BC and BA|
vector BC = column vector = [1-1, 0-4, 2-3] = [0, -4, -1]
vector BA = column vector = [2-1, 1-4, 4-3] = [1, -3, 1]
Take cross product of these 2 vectors using determinants = square root of (66) = 8.1240 ...
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What uni course is this from?