设的内角、、的对边分别为、、,且满足.则______. 答案:【答案】4【解析】解法1 有题设及余弦定理得 .故 .解法2 如图4,过点作,垂足为.则,.由题设得.又,联立解得,.故.解法3 由射影定理得.又,与上式联立解得,.故. 55. Because of his English, he couldn’t talk to the foreigner . A. limiting; free B. limited; free C. limited; freely D. limiting; freely