If more than eight bits were used for the host portion, this method would not work. However, because less than eight bits are used for the host portion, you can assume that the starting network ID for these subnets is the first three octets of the host$$s IP address $(192\mathrm{.}168\mathrm{.}89)$ with $0$ in the final octet. This means you can now fill in enough information about this host$$s subnet and the surrounding subnets to find the information you need.