Find the area of the shaded region of the circle.

Answer:
About 9,346.2 mm²
Step-by-step explanation:
First, find area of the smaller circle and the larger circle.
[smaller]
πr²
π25²
Around 1,963.5
[larger]
πr²
π60²
Around 11,309.7
[find shaded region]
Larger / shaded - smaller = around 9,346.2 mm²