Вставить слoва i don't want to live in the centre because it's and

1 . noisy
2 . crowded

решение. 1. ri=2*r; rii=r/2; ri/rii=4; не надо ни о какой площади сечения говорить. два куска проволоки содинили последовательно, получили ri=2*r; два куска той же проволоки соединили параллельно, получили rii=r/2; ну, а теперь раздели первое на второе!

а теперь общий случай: ri=r*n; rii=r/n; ri/rii=n^2; кусок проволоки разрезали на n одинаковых кусков. сначала эти куски соединяют последовательно: ri=r*n; затем соединяют параллельно rii=r/n; ну и дели первое на второе и делай выводы.

1 Lawrence Ferlinghetti opened the oldest paperback book store in the United States in 1953.
The oldest paperback book store in the United States was opened in 1953 (by  Lawrence Ferlinghetti).
2 The police are interviewing him in connection with the armed robbery.
He is interviewed in connection with the armed robbery (by the police).
3 More than a billion people all over the world speak English.
English is spoken all over the world (by more than a billion people).
4 They will officially announce their engagement tomorrow.
Their engagement will be officially announced tomorrow.
5 Tom is not going to invite me to his party.
I'm not going to be invited to the party (by Tom).
6 Our physical education teacher can make a good basketball player of every pupil.
Every pupil can be made a good basketball player (by our physical education teacher).