Area of Triangle (삼각형의 넓이)

Computing the area of a triangle using vectors
The area of a parallelogram embedded in a three-dimensional Euclidean space can be calculated using vectors. Let vectors @@\textbf{AB}@@ and @@\textbf{AC}@@ point respectively from @@A@@ to @@B@@ and from @@A@@ to @@C@@.
The area of parallelogram @@ABDC@@ is @@|\textbf{AB} \times \textbf{AC}|@@ which is the magnitude of the cross product of vectors @@\textbf{AB}@@ and @@\textbf{AC}@@.
And the area of triangle @@ABC@@ is half of this, @@\large{\frac{1}{2}} \normalsize{ |\textbf{AB} \times \textbf{AC}|}@@.