cho tia oc nằm giữa hai tia oa và ob biết góc aOb = 85 độ và góc aOc nhỏ hơn bOc là 15 độ . tính số đo góc aOc và bOc

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Đoạn 1 Wild animals play an important part in the balance of nature and supply us with many important items. Birds and other small animals help control insects. Wild animals provide food and hobby too. Furthermore ,they make our surrounding more interesting. Uncontrolled hunting has destroyed a lot of wildlife and people have also harmed animals such as the passenger pigeon which disappeared completely. Others including the whooping cranes, the blue whale and the American alligator are in danger of dying out. Something it is necssary to keep animals from becoming too plentiful. For example, rabbits and such rodents as squirrels and mice may cause great damage to crops if they are too abundant. Predators hold down the population of the their prey. Đoạn 2 The origins of the olympic Games can be traced back to ancient Greece, to as far back as 776 B. C. It was a Greek tradition to hold athletic competitions every four years in honour of the their gods or dead heroes. The prizes awarded to the winners of each event in those days were a crown of olive and a palm branch. Although this may seem meaning less in modern times, the true prize lay in the honour of having won the event. The winners were given places of honour on public occasions. In some towns they even exempted ( be free) from paying taxes. The first modern Olympic games were held in Athens in 1896. Since then , nations from around the world have been meeting every four to complete againts one another. New Olympic rea=cords are set every time they meet. The only exception to this quadrennial event was in 1944, when the Olympic games were not held because of the Second World war. GIAI CAI NAY GIUM TUI CÂU NÀY DỊCH SANG TIẾNG VIỆT NHA TRÂN THÀNH CẢM ƠN NHƯNG KO ĐC SAO CHÉP TRÊN MẠNG MÀ HÃY TỰ MÌNH LM NHA