tren duong thang d cho 3 diem A,B,C sao cho AB=6cm,AC=4cm.a,tinh do dai BC .b,1 diem O nam ngoai duong thang d sao cho goc AOB=70 do ,goc AOC=30 do .tinh BOC
Cho goc xOy=50 do .Ve tia Oz sao cho goc xOz=70 do .Tinh goc yOz
mot hoc sinh lam mot mat dong ho nhu hinh 4. hay do de kiem tra xem dong ho do ke dung hay sai
tren duong thang x'x lay 1 diem O .tren cung 1 nua mat phang bo x'x ta ke 3 tia OY;Ot;Oz sao cho goc x'Oy la 42 do goc xOt ls 97 do va goc xOz la 56 do .a,chung to Ot nam giua 2 tia Oy,Oz .b,chung to Ot la tia phan giac cua goc zOy
cho goc AOB va tia OC la phan giac cua goc do. Ve tia phan giac OM cua goc BOC.Cho biet goc BOM=35o.Tinh so do cua goc AOM
cho 20 diem phan biet , trong do co dung 7 diem thang hang , ngoai ra khong co 3 diem nao thang hang.cu qua 2 diem ta ve duoc 1 duong thang.hoi tu 20 diem do ta ve duoc bao nhieu duong thang
cho A1,A2,A3,...,A100 trong do khong co 3 diem nao thang hang. goi S la tong cac doan thang nhan hai diem trong cac diem do lam dau mut. Hay so sanh S voi 5000
Cho 3 diem thang hang A,B,C sao cho B nam giua A va C.Lam the nao de chi do 2 lan,ma biet duoc do dai cua 3 doan thang AB,BC,AC?hay neu cac cach lam khac nhau.
Giúp mk nha mk cần gấp!!!!!
1) cho goc bet xoy ve tia oz sao cho goc xoz=70*
a) tinh goc zoy
b) tren nua mat phang bo ox chua oz ve tia ot sao cho xot=140* chung to tia oz la tia phan giac cua goc xot
2) cho 2 goc ke bu goc xoy , yoz biet goc xoy=140*
a)tinh so do goc yoz
b) ve tia phan giac ot cua goc xoy tinh so do goc xot ,zot
3) cho hai goc ke bu xoy, yoz biet goc xoy=40*
a) tính so do goc yoz
b) ve tia ot la tia phan giac cua goc yoz tinh ó do goc yot goc xot
4) cho goc bet xoy ve tia oz sao cho goc yoz= 60*
a) tinh so do goc zox
b) ve tia om,on lan luot la tia phan giac cua goc xoz,yoz hai goc zom, zon co quan he gi giai thich