How does the distance of a planet from the sun affect the temperature?

[ohxhowtragic]

my evil teacher is making me and my friend to do a 12 page report. and the question is "how does the distance of a planet from the sun affect the temperature?" i would really apperciate it. thanks.

 

[Atomos]

As radiation propagates in all directions equally (in a sphere) the intensity of that radiation varies inversely with distance.

If radiation propagates in all directions equally, the intensity is strength of the source divided by the surface area of of the resulting sphere. You will be able to derive an expression fro the intesity per unit area of the sphere if you know the formula for the surface area of a sphere.

 

[Danger]

If it won't get you in trouble, you might also point out that distance is not by any means the only thing governing the temperature. You also have to factor in albedo and atmospheric composition. In the case of many planets, you also have the core activity generating heat. I suspect, but am not sure, that if it's rapid enough, plate tectonic movement will generate frictional and compression heat.
As Atomos said, your solar radiation (any radiation, and gravity for that matter), decreases as the square of the distance.