cho o trung diem doan thang ab. tren cung mot nua mat phang bo ab ve cac tia ax, by cung vuong goc voi ab. lay c bat ki tren ax roi ve duong thang vuong goc voi octai o cat by o d.   chung minh a, oc la phan giac goc acd   . b,   ca= ac + BD

cho goc xOy khac goc bet ,ot la tia phan giac cua goc do .tren tia ot lay diem H,qua H ve duong thang vuong goc voi tia ot,cat Ox tai A va Oy tai B

chung minh tam gic AHO bang tam giac BHO

tren tia Ax lay diem C tren tia By lay diem D sao cho AC=BD.chung minh AD=BC

cho CD cat tia ot tai diem K .chung minh AB song song voi CD

cho▲abc co ab=6cm,ac=8cm,bc=10cm.goi k la trung diem cua doan thang bc duong trung truc cua doan thang bc cat ac tai m goi d la hinh chieu vuong goc cua c tren duong thang bm .cmr a)▲abc vuong tai a b)AB=DC c)3 duong thang AB,MK,CD di qua 1 diem giup minh voi mai mình phải nop cho co roi

cho doan thang ab co o la trung diem va d la duong trung truc. tren d lay diem m.qua ke duong thang vuong goc voi am va cat d tai n

cmr:a,tam giac anb can

b,tam giac amn=tam giac bmn va goc mbn = 90 do

giup minh nha

Cho tam giac ABC nhon. M la trung diem cua BC. Duong thang BD vuong goc voi AB cat AM tai E. Tren doan thang AM lay diem D xao cho MD = ME. Chung minh AB vuong goc voi CD

Bai 5: Cho goc xOy nhon, Ot la tia phan giac cua xOy. Tren tia Ot lay diem H, qua H ve duong thang vuong goc voi Ot cat Ox tai A, cat Oy tai B.

a/ Chung minh \(\Delta AHO=\Delta BHO\)

b/ Tren tia Ax lay diem C, tren tia By lay diem D sao cho AC=BD. Chung minh AD=BC

c/ CD cat tia ot tai K. Chung minh AB / / CD

mn giup em vs ak

cho tam giac ABC can o A.Tren canh BC lay diem D, tren tia doi cua tia CB lay diem E sao cho BD=CE.Tu D ke duong thang vuong goc voi BC cat AB o M, tu E ke duong thang vuong goc voi BC cat AC o N.Chung minh:

a)MD=ME

b)MN cat DE o I. Chung minh I la trung diem cua DE

c)Tu C ke duong thang vuong goc voi AC, tu D ke duong thang vuong goc voi AB.Chung cat nhau tai O.Chung minh AO la duong trung truc cua BC