JJ.36 Bending paper tape right-angled

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.


    











Answer
(1) 2 cm2
(2) 70 cm2
(3) 5 cm

Reference