$A+33\mathrm{.}316,+39\mathrm{.}072km2\mathrm{.}0,4\mathrm{.}0,2\mathrm{.}0AA,B,C,D,$ and A gives elevation differences $(in$ meters$)of-16\mathrm{.}49,+33\mathrm{.}316,+39\mathrm{.}072,$ and $-55\mathrm{.}883,$ and distances $inkmof2\mathrm{.}0,4\mathrm{.}0,2\mathrm{.}0,$ and $4\mathrm{.}0,$ respectively. The elevation $ofAis634\mathrm{.}597.$Differential leveling between BMs A$,$ B$,$ C$,$ D$,$ and A gives elevation differences $($in meters$)$ of $-16\mathrm{.}49,+33\mathrm{.}316,+39\mathrm{.}072,$ and $-55\mathrm{.}883,$ and distances in km of $2\mathrm{.}0,4\mathrm{.}0,2\mathrm{.}0,$ and $4\mathrm{.}0,$ respectively. The elevation of A is $634\mathrm{.}597.$