ii) is weird, don't really understand what to do there.
iii) Say AD = 6
So then AB = 2, BC = 2, CD = 2
(they're all equidistant [didn't even know that was a word...])
Area of semicircle AD = 4.5 pi
Area of semicircle AB = ½ pi
Area of semicircle BD = 2 pi
Area of new shape = (Area of...