I have the double integral of...

∫∫y^3 dA

and the region 'D' are the points:

(0,2),(1,1),(3,2)

I graphed it, it makes a triangle but how in the world can I set up my integral like this? I really don't see an upper and lower equation, but I do see the ends of the region I can take.

If I fix 'x' I can go from 0 to 3

If I fix 'y' I can go from 1 to 2

but now what do I find? or how do I find it for that matter...