Two parallel rectangles with dimensions $3$ftx$5$ft are spaced apart by a distance of $1$ ft $.$ The Bottom plate has an emmisivity of $\mathrm{.}9$ and the top plate has an emmisivity of $\mathrm{.}8.$where the top rectangle receives a total of $180,000$Btu$/$h radiation heat transfer rate from the bottom rectangle. If the top rectangle has a uniform temperature of $60$F$,$ determine the temperature of the bottom rectangle.