Finding an objects surrounding temperature

[Xek_0003ad64]

Homework Statement

Hi, I have just started with physics and this is my first time posting on this forum, The question is very confusing. it asks:
What is an objects surrounding temperature (T0) if we know the:
A=1.5
T=303 K
σ=5.67x10^-8
ε=.9
P (net radiated power gained)= 155 W

See attachment, question 3(c)

Homework Equations

either;
P=εσA(T^4-T0^4) or εσAT^4

The Attempt at a Solution

I have not made an attempt, the answer of the first equation requires both surrounding temperature (T0) and the temperature of the object (T) but the answer would be the rate at which an object radiates energy; in joules, not watts (from what I understand) but the other equation doesn't have the T0, so you can't use algebra to solve it.
Please don't just type the answer, explain how you got it.

Thanks.

 

[CWatters]

You appear to have all the info needed to solve your equation for T0 using..

P=εσA(T^4-T0^4)

where P is in Watts. One Watt = one Joule per second.

P=εσAT^4 - εσAT0^4

εσAT0^4 = εσAT^4 - P

T0^4 = T^4 - P/εσA

T0 = (T^4 - P/εσA)^-4

Substitute..
A=1.5
T=303 K
σ=5.67x10^-8
ε=.9
P (net radiated power gained) = 155 W = 155 J/S