  In the framework of the Kompaneets approximation the propagation of a shock
front (SF) in inhomogeneous medium with the power-law density decrease at the
exponent $n=2$ is investigated. For this important case corresponding to outer
regions of the solar and stellar coronas an unexpectedly simple exact solution
clearing a structure of the general solution for an arbitrary monotonic density
of medium is found. Our results for plane-layered medium are compared to the
Korycansky one for off-centre explosion in radially stratified medium. The
relation between the solutions in these media are found and a new exact
solution for a noncentral explosion in the case of density singularity on the
finite radius is received.
