bedbed27bed
幼苗
共回答了12个问题采纳率:83.3% 举报
小题1:(1)连结
交
6 于
,····················· 1分
当顶点
与
重合时,折痕
垂直平分
6 ,················· 1分
,
····················· 2分
在矩形
中,
,
,···························· 3分
.···························· 3分
································ 4分
四边形
3 是菱形.
小题2:(2)证明:过
作
5 交
6 于
7 ,
由作法,
,··························· 5分
由(1)知:
,又
,
,···························· 6分
,则
······················· 7分
四边形
3 是菱形,
,
.······
1年前
4