Answer:
8.4 kW
Step-by-step explanation: 
Using the Stefan-Boltzmann law,
P = εAσT4
Where: 
P: Radiation Energy 
ε: Emissivity of the Surface. Check emissivity table below of common materials. 
A: Surface Area, in m^2. 
σ: Stefan-Boltzmann Constant, σ=5.67 × 10-8 W/m2•K4 
T: Temperature
Plugging in values, 
P = 0.85 x 3.328 x 5.67 x 10^(-8) x 205
P = 8383 W or 8.4 kW