2 * pi * r
12500 * 3.14 * 2 = 78,500 miles
(pi * r)^2
12500 * 12500 * 3.14 = ~490,000,000 sq miles
According to the Flat Earth map, the earth's best known diameter is 25000 miles so the circumference of the ice wall would be about 78500 miles. Assuming that is correct the earth is about 490 Million square miles. The ice wall is about 200 miles thick or about 1.6% of the earth's diameter. That makes it about 7.84 million square miles. HTH.