Measuring Solid Angle of Cuboid: Steradians

[Atran]

Hi, How can I measure one solid angle of a cuboid, at least a non-sphere shape?
I've read about steradians on internet, so I haven't studied it in any textbook.

Thanks...

 

[Atran]

A cuboid with the sides (a), (b) and (c).
I think the total steradians of it is 360²=(129600*π)/360=720π

V = a*b*c
V = (4π(r³))/3

((3*a*b*c)/4π)^(1/3) = r
((3*a*b*c)/4π)^(2/3) = r²

((3*a*b*c)/4π)^(2/3) * 720π = A

Is that procedure correct?

 

[Atran]

I think the total steradians of it is 360²=(129600*π)/360=720π

I wrote incorrect above, right?
If a circle and a rectangle have totally 360 degrees, therefore a sphere has the same amount of degrees (4π) as a cuboid has.

So this should be incorrect ((3*a*b*c)/4π)^(2/3) * 720π = A),
and the correct one should be: ((3*a*b*c)/4π)^(2/3)) * 4π = A

All I want is to measure one point's degrees in a cuboid.

 

[g_edgar]

Don't use 360^2. That would be stedegrees or something. Not steradians.