A company has been allocated a network ID $=200\mathrm{.}122\mathrm{.}0\mathrm{.}0/18$ for its network and is required to create $3$ subnets for the network $[$Show your workings$]$

$(1)$ State the default subnet mask in dotted decimal form.

$($ii$)$ Provide the range of usable IP address for all three subnets.

$($iii$)$ State the broadcast address for the second subnet.

$($iv$)$ Specify the IP address of the $21$th host in the second subnet