Need help with how to work the problem below. The answer key says the answer is 12,700 mi squared but I don't know how they got that.

"The athletic dept. at Pi High School is planning a circular track 400 m long. The area inside the track will be planted with sod. About how many square meters of sod will be needed? (round to the nearest 100 m squared"
Thanks...

surely you know that the area of a circle is πr^2, and that the circumference is 2πr.

So, 2πr = 400, making r=200/π

Thus, the area is πr^2 = π(200/π)^2 = 40000/π = 12732

Round that to get the answer.