Answer:
Step-by-step explanation: Since the rectangle sits within the larger circle, let's look at it this way:
Area of Shaded Region = Area of Circle - Area of Rectangle
OR
(X) =( pi * r^2 ) - (rectangle length * rectangle width)
Now we fill in the numbers where we know the numbers:
(X) = (pi * (12 cm)^2) - (3cm * 10cm)
(X) = (pi * 144cm^2) - (30 cm^2)
(X) = 144pi - 30
(X) = 452.39 - 30
(X) = 422.39 cm^2