$9\mathrm{.}30($a$)$ Given d$=1\mathrm{.}2$ in$.$ and L$=100$ ft$,$ calculate $.($b$)$ Given d$=0\mathrm{.}5$ ft and g $=0\mathrm{.}00030,$ calculate L$.($c$)$ Given L$=1000$ in$.$ and g $=0\mathrm{.}00042,$ calculate d$.$