AD = BD = 1CD = √3勾股定理得AC = 2
http://zhidao.baidu.com/link?url=GiZFibMUImB8o-EJRD6b3yRvh5y3ntgUCx7CsBNn61UotOoTYLSleNtg5dWyYAAGR6jwASsz36YuvgZ2VQBBmwAQ5bK8BiRcnDX6oye_mp_请参考,懂了记得选满意,不懂欢迎追问。答题不易呀。