Объясни смысал выражений:Нащупывая слабые места взрослых

помогите периметр квадрата равен 20 дм.Чему равен периметр равностороннего треугольника с длиной стороны, как у квадрата?

НА ЗАВОД ОТПРАВЛЕНО 3600 Т. УГЛЯ В ВАГОНАХ ПО 60 Т . В КАЖДОМ И СТОЛЬКО ЖЕ УГЛЯ В ВАГОНАХ ПО 90 Т. В КАЖДОМ КАКИХ ВАГОНОВ ПОТРЕБОВАЛОСЬ БОЛЬШЕ И НА   СКОЛЬКО БОЛЬШЕ ?
 

Complete the aenences with the verbs in brackets in correct form. 1. The travellers had to stop/ It was difficult to walk-exerything............................(cover) with deep snow. Here and there the great branches.....................(tear away) by the wind. 2. At last the boys came up to they mysterious old house.................(explore) before. 3/There was no more talk. The basket ..................(unpack). Everybody was ready to do something or to fetch something. In a few minets supper was ready. 4. Jane and Michael could not rememer that thay ..............(put) to bed so quickly as they were that night. Marry Poppins blew out the light very early and hurriedly went away. Помогите пожалуйста.. Можно в ключах... ....Заранее спасибо...