..... Process:

Let the radius of the big circle be r and the radius of the small circle be r; According to the meaning of the question

1/2(R？ -r？ )=300

So, (r? -r？ )=300×2;

And, the ring area =(R? -r？ )×3. 14

=300×2×3. 14

= 1884cm？ ..........................