如图,△ABC的介质中,AB = AC,∠A = 36?6,AC AB的垂直平分线相交于E,D踏板连接EC(1).查找∠的ECD度(2)求∠ECB程度
问题描述:
如图,△ABC的介质中,AB = AC,∠A = 36?6,AC AB的垂直平分线相交于E,D踏板连接EC(1).查找∠的ECD度(2)求∠ECB程度
答
(1)∵DE垂直平分AC,∴CE= AE,∴∠ECD =∠A = 36?邱R>(2)∵AB = AC,∠A = 36?邱R>∴∠B =∠ACB =72?邱R>∴∠BEC =∠A +∠ECD = 72?邱R>∴∠BEC =∠B,∴BC = EC = 5.答:(1)∠ECD是36度?·R>(2)BC的长度是5....