There is paper tape 2 cm in width.
Bending this paper tape right-angled several times as shown in Fig. 1.
As shown in Fig. 2, it is finally made for an overlap of each end of the paper tape to be a square whose one side is 2 cm.
(1) As shown in Fig. 1, when you bend a paper tape once, find the area decreased by bending.
(2) The form as shown in Fig. 2 was made using a paper streamer 40 cm in length. Find the area of a shadow area.
(3) In Fig. 2, when rectangle ABCD is set to AB : BC = 1 : 2, find the length of AB.