Duplicatge post.. See https://www.cakecentral.com/forum/t/848689/need-guidance-with-cake-pan-size-1
I've been thinking about this regarding the # of servings. I'm thinking there could be 20 servings if it was only 1 layer (2").
\You also could use a sq pan but would have to do more cutting & rearanging
industry standard is 1x2x4 inches of cake, or 8 square inches per serving
"party size" some use is 1.5 x 2x4, or 12 square inches.
20 servings is 160 to 240 square inches of cake 4" high.
7x11x4= 308 square inches of cake. OR 159 inches if only a single layer of 2".
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The prayer rug is 2.5 feet by 4 feet, to make it look dimensionally correct. So you need a pan (or cut down cake size) that is 7x11, or <<< (small side) times 1.6= large side.>>>
It probably depends on what pans you already have, or if you want to cut it down to make an extra number of servings.
I baked a 13x9 and made it 3 inches tall. It worked out. Thanks for all your help, everyone. 
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