Circle P6 2010 SA2 HHK P2 Q13

The figure below shows 2 quarter circles and a rectangle. The radius of the big quarter circle is 8 cm. The radius of the small quarter circle is 4 cm. Find the difference in area between the two shaded parts X and Y. Use the calculator value of pi and give your answer correct to 1 decimal place.

1/4 x ∏ x 8 x 8 = 16 pi

1/4 x ∏ x 4 x 4 = 4 pi

16 pi - 4 pi =  12 pi  B + X

8 x 4 = 32       B + Y

12 pi  - 32 = 5.7 cm2

It was 5.7 cm2.

Please calculate ?? as I do not have a proper calculator.