The largest circle has radius OP = 8 cm, the next largest circle has radius AO = 4 cm, and the smallest circle has diameter AB = 4 cm so its radius has length 2 cm.
These circles have respective areas of 64π cm², 16π cm², and 4π cm².
The area of the shaded region is then
64π cm² - 16π cm² + 4π cm² = 52π cm²