Answer
464,229 Watts
Work Step by Step
a) We use the equation for the rate of heat conduction, which is equation 16.5 in the book, to obtain:
$H = -\frac{(80.4)(4.6)(3)}{.004}=277,380 \ Watts$
b) We use equation 16.9 in the textbook to find the rate of heat radiation:
$P = (1)(5.67\times10^{-8})(4.6)(920)^4=186,849 \ Watts$
c) Thus, the total loss is: $\fbox{464,229 Watts}$