tolong banget dijawab, beserta caranya:) makasih

L = p.l = 0,285.l = 137 => l = 480,7 cm = 4,8 m 
Pk = k.Ak.ΔT/L = 1/8.(4,8.0,025).30/0,025 = 18 Watt
Ps = k.As.ΔT/L = 3/2.(4,8.0,01).30/0,01 = 216 Watt
Pb = k.Ab.ΔT/L = 1.(4,8.0,25).30/0,25 = 144 Watt
P total = Pk + Ps + Pb = 18 + 216 + 144 = 378 Watt