I need help!


The figure is made up of 6 identical quarters and 2 identical semicircles. The radius of each quarter circle is 20cm.
a) The unshaded part marked A is enclosed by 2 quarter circles and 2 semicircles. What is the perimeter of A?
b) What is the total area of the shaded part?
(Take n=3.14)

http://books.google.com.sg/books?id=S0fOchUXUu0C&pg=PA35&lpg=PA35&dq=the+figure+is+made+up+of+6+identical+quarter+circles+and+2+identical+semicircles&source=bl&ots=AiO8cOlZYB&sig=FSnU9HM2zAH9FkQOfLzWyhJP87A&hl=en&sa=X&ei=xGnaUeXEFcrMrQfZh4CgDQ&ved=0CFgQ6AEwCA#v=onepage&q=the%20figure%20is%20made%20up%20of%206%20identical%20quarter%20circles%20and%202%20identical%20semicircles&f=false