A long support column of trapezoidal cross section is well insulated on its sides, and temperatures of $100$ and $0C$ are maintained at its top and bottom surfaces, respectively. The column is fabricated from AISI $1010$ steel, and its widths at the top and bottom surfaces are $0\mathrm{.}3$ and $0\mathrm{.}6m,$ respectively. Steel, AISI $1010(323$K$)$: $k=62\mathrm{.}7\frac{W}{m}K.$