[Toán 9]nhận biết tứ giác

A

alonebycs312

K goi tu giac do la ABCD vs 2 canh doi AB=CD va dg cheo AC=BD cat nhau tai O
noi BC cm tam giac ABC=DCB (c.c.c)\Rightarrow goc DBC=ACB\Rightarrow tam giac 0BC can tai O
tu do suy ra tu giac co 2 dg cheo bang nhau va cat nhau tai trung diem moi dg nen la hcn@};-@};-@};-
 
You must log in or register to reply here.
Top Bottom