[en] The weak angle is formulated in the U(4) space, where this angle is given as a difference of rotation angles between about ''7''-axis and ''10''-axis. Then, assuming that the weak angle and SU(2)xSU(2) breakdown derive from a common origin, these angles are determined as thetasub(p)=+-2.6⁰ and thetasub(n)=+-11.1⁰. In our determination, the difficulty concerning the u₃ term is eliminated. Further, our determination predicts that the mass term of fourth quark d asymptotically equals 30, i.e., msub(D) asymptotically equals 2.0 GeV, which is consistent with preliminary analyses of mass of super hadrons. (auth.)