Calculate the area of the shaded region.

Let be the area of the sector in the larger circle (radius 12 cm) whose central angle is subtended by the labeled arc with measure 45 deg, and let be the area of the sector in the smaller circle (radius 8 cm) with the same central angle. The area you want is .

We have

So the area of the shaded region is .

Step-by-step explanation:

The other factor has 4 decimal places because the number of decimal places in a product is the sum of number of decimal places in the factors.

Example = 4.3 * 2 = 8.6

      4.3 * 0.2 = 0.86