  In this paper we use the symmetry reduction method to obtain invariant
solutions of the ideal magnetohydrodynamic equations in (3+1) dimensions. These
equations are invariant under a Galilean-similitude Lie algebra for which the
classification by conjugacy classes of r-dimensional subalgebras ($1\leq r\leq
4$) was already known. So we restrict our study to the three-dimensional
Galilean-similitude subalgebras that give systems composed of ordinary
differential equations. We present here several examples of these solutions.
Some of these exact solutions show interesting physical interpretations.
