Applet 4.3 : Determinants for 3*3 Matrix 
Applet 2 : Determinant (Vectors by Entry)

For vector u , v , w
,
if A = [ u , v , w ] in the 3*3 matrix, then geometrically
Det(A) is the volume of the parallelepiped with sides u , v and
w.
This applet is a dragable applet by which we can drag the parallelogram. The Applets given below shows an interactive visualization of this idea. Applet 1 : Determinant (Dynamic selection of Vectors) Applet 2 : Determinant (Vectors by Entry) 
: 