25.13cm^2 or 8pi. The radius of a circle is 2 x pi x r^2. R is the radius. 2 x pi x 2^2cm -> 2 x pi x 4cm -> 8cm x pi -> 25.13cm^2. Leaving the answer in terms of pi would be 8pi.
21000 people paid for general admission and 6000 paid for reserved seats. This is solved by making 2 equations. Out of 27000 people who were at game, x of them paid for general admission and y for reserved seats, thus
x + y = 27000
As said, daily receipts were 204000$. As reserved seat is 13$, y of them gave 13$ each (y*13$) and x of them gave 6 for general admission(x*6) and those two add up and we get second equation
13y + 6x = 204000.
This can be solved by transforming first equation into x = 27000 - y and then replacing the x in second.
13y + 6*(27000 - y) = 204000
13y + 162000 - 6y = 204000
7y = 42000
y = 6000
x + 6000 = 27000
x = 27000 - 6000 = 21000