What an odd question. You will have to answer it yourself, after first answering these preliminary questions:
- How thick should it be when spread?
- If it goes down to a layer 1 atom thick, how far apart should the atoms be? In theory you could make all the atoms in your brain into a 2D 'web' which would cover probably billions of square miles.
Basically it's a question of maths, I did this level of difficulty when I was about 7 years old so I've forgotten some of it, but surely you can find out the volume of the average human brain on the internet? Once you know this, and how thick you want the layer to be, it's easy. Divide the volume by the thickness.
If you're going for the 'web of atoms' approach, the fact that this q was asked in the first place puts your ability to compute this into question. You will need the chemical composition of the brain (simplify this by using maybe 70% water and 30% proteins/fats) and the weight. Use molar masses to estimate the total number of atoms in the brain, decide how far apart you want them to be, what shape of web etc. and proceed from there.
It could cover an area of 1500 miles by 1500 miles
82.26 sq mi
300 square miles = 192000 acres 300 square miles = 77699.643309 hectares 300 square miles = 7.7699643309e+28 square angstroms 300 square miles = 8.6809994583e-24 square light years 300 square miles = 76799.999999 square city blocks [Midwest U.S.] 300 square miles = 3717119999.9 square cubits 300 square miles = 776.99643309 square kilometers 300 square miles = 1105915576.8 square varas [California] 300 square miles = 479627427.83 tatami [Japan] 300 square miles = 227265.70117 arpents [Canada]
58.4 square miles.
10,931 square miles (28,311 square kilometers).
It cover 500 thousand square miles.
The Great Lakes cover approximately 94,250 square miles in total.
It is 250,950 square miles.
52,271 square miles.
Syria is 71,998 square miles.
1000 square miles
6.14 x 2.61 = 16.0254 square inches = 0.00000000399188978 square miles x 1000000000 = 3.99188978 square miles. Call it 4 square miles.
Cardiff's area is 54.17 square miles.
Approx 3705400 square miles.
15.444 square miles
Lille, France - 15.25 square miles.
about 64 square miles