Ve tren cung mot hinh theo cach dien dat sau :
a)Ve 4 diem A ,B ,C D sao cho C nam giua A, B va 3 diem A, B D ko thang hang . Hay ve va ke ten duong thang (phan biet) di qua tung cap diem .
b) Ve diem E sao cho E va D nam khac phia doi voi A . Ve diem F sao cho C,E,F thang hang va F thuoc duong thang DB
Cho cac diem A va B thuoc duong thang a,diem C nam giua A va B.diem D nam giua C va B.cau hoi;a,tim tren hinh ve cac tia doi nhau goc C.b,dung lap luan chung to C nam giua A va B.c,tren hinh ve co bao nhieu doan thang?la nhung doan thang nao
Cau 5: Trong cac khang dinh sau, khang dinh nao dung, khang dinh nao sai?
1.Ba diem phan biet la ba diem thang hang.
2.Voi ba diem phan biet luon co hai diem nam ve cung phia doi voi diem con lai.
3.Voi ba diem thang hang phan biet luon co hai diem nam khac phia voi diem con lai.
4.Voi ba diem A,B,C thang hang thi diem B luon nam giua hai diem A,C.
5.Co mot va chi mot duong thang di qua hai diem (phan biet) cho truoc.
6.Hai duong thang phan biet thi song song voi nhau.
7.Hai tia chung goc thi cung nam tren mot duong thang.
8.Hai tia chung goc thi doi nhau
9.Neu diem M nam giua diem A,B thi no la trung diem cua doan thang AB.
10.Neu MA=MB thi M la trung diem cua doan thang AB.
11.Neu MA+MB= AB va MA=MB thi M la trung diem cua doan thang AB.
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ve 4 diem A,B,M,N sao cho diem A nam giua M va B , diem N nam giua A va B
a ) hay cho biet diem A nam giua 2 diem nao .
b ) Tim cac diem nam cac phia doi voi A
Bai 1
Cho tam giac nhon ABC , diem M thuoc canh BC , goi D la diem doi xung voi M qua AB , goi E la diem doi xung voi M qua AC. Goi I,K la giao diem cua DE voi AB va AC
a,CMR ; MA la tia fan giac cua goc IMK
b,Tim vi tri cua diem M de DE co do dai nho nhat
Bai 2
Cho hai diem A va B nam cung phia doi voi duong thang d.goi AH , BK la cac duong vuong goc ke tu A , B den d.Goi C la diem bat ki nam giua H va K
a,Ve diem A' doi xung voi A.cmr goc ACH = goc A'CH
b,Gia su goc ACH = goc BKC ,cmr khi do 3 diem A',C,B thang hang
c,Neu cach dung diem C nam giua H va K sao cho goc ACH = goc BKC
SACH CAC DANG TOAN VA PHUONG PHAP GIAI LOP 8
Ve tia Ox va tia Oy doi nhau.Ve diem A thuoc Ox,cac diem B va C thuoc tia Oy (B nam giua O va C)
a,Hay ke ten cac tia trung voi tia OB
b,Tia Ox va tia By co phai la 2 tia doi nhau ko?Vi sao?
c,Hay ke ten cac doan thang tren duong thang xy
a, Các tia trùng với tia OB là: AB; AC; OC.
b, Ox và By không phải là 2 tia đối nhau vì 2 tia này không có chung gốc.
c, Các đoạn thẳng trên đường thẳng xy: AO; AB; AC; OB; OC; BC.
cho 2 diem M va N nam Cung phia voi A , nam cung phia doi voi B . Diem M nam giua A va B . biet AB =3cm,BN=1cm.chung to rang:
a, bon diem ABMN thang hang
b, diem N la trung diem cua doan MB
c , ve dung tron tam N di qua B va duong tron tam A di qua N , chung cat nhau tai C tinh chu vi tam giac CAN
cho 2 diem M va N nam Cung phia voi A , nam cung phia doi voi B . Diem M nam giua A va B . biet AB =3cm,BN=1cm.chung to rang:
a, bon diem ABMN thang hang
b, diem N la trung diem cua doan MB
c , ve dung tron tam N di qua B va duong tron tam A di qua N , chung cat nhau tai C tinh chu vi tam giac CAN
cho hai diem M va N nam cung phia doi voi A,nam cung phia doi voi B. diem M nam giua Ava B biet Ab =5 cm AM =3cm BN=1cm .CMR BON DIEM A ,B , M,M nam thang hang va diem N la trung diem cua doan thang MB
