  Based on the geometry of entangled three and two qubit states, we present the
connection between the entanglement measure of the three-qubit state defined
using the last Hopf fibration and the entanglement measures known as two- and
three-tangle. Moreover, the generalization of the geometric representation of
four qubit state and a potential entanglement measure is studied using
sedenions for the simplification of the Hilbert space S^31 of the four qubit
system. An entanglement measure is proposed and the degree of entanglement is
calculated for specific states. The difficulties of a possible generalization
are discussed.
