Final answer:
To find the area of the shaded region between two circles, calculate the area of the larger circle with the formula A= πr² and subtract the area of the smaller circle from it. Express the final answer by appropriately rounding to the correct number of significant figures.
Step-by-step explanation:
The student is asking about finding the area of the shaded region between two circles with different radii. To find this area, we must calculate the area of the larger circle and subtract the area of the smaller circle from it using the formula A = πr².
First, let's find the area of the larger circle which has a radius of 11 cm:
Alarge = π × (11 cm)²
Next, we'll compute the area of the smaller circle with a radius of 9 cm:
Asmall = π × (9 cm)²
The shaded region's area is the difference between these two areas:
Area of shaded region = Alarge - Asmall
Area of shaded region = (π × (11 cm)²) - (π × (9 cm)²)
After plugging into a calculator, remember to round the answer according to the number of significant figures provided by the radii (in this case, two significant figures).