Area and Volumes

圖片參考：http://farm4.static.flickr.com/3342/3425664363_3492be5869.jpg?v=0

[Given that the radius of the circle is 2cm]
The perimeter of the shaded region
=2*[(1/2)*circumference of the circle]+4+4
=2*[(1/2)*2π(2)]+8
=4π+8
~20.6cm

2009-04-09 21:32:06 補充：
* means product

the perimeter of the shaded region=4+4+2π(2)
=(8+4π)cm

The perimeter of the shaded region in the figure:

( 8 + 4π ) cm