cho tam giac ABC can tai A duong cao AH biet AB=5cm,BC=6cm.
a)tinh do dai cac doan thang BH,AH
b)Goi Gla trong tam cua tam giac ABC . Chung minh rang ba diem A,G,H thang hang.
c)Chung minh hai goc ABG va ACG bang nhau
cho tam giac abc can tai a(goc a nhon, ab>bc). goi h la trung diem bc
A)chung minh tam giac ahb=tam giac ahc va ah vuong goc voi bc tai h
B)goi m la trung diem cua AB. Qua A ke duong thang song song voi BC, cat tia HM tai D. Gia su AB=20cm,AD=12cm. Chung minh AD=BH. tinh do dai doan AH.
C)tia phan giac cua goc BAD cat tia CB tai N. Ke NK vuong goc voi AD tai K, NQ vuong goc voi AB tai Q. Chung minh AQ=AK va goc ANQ=45do + 1/4gocBAC
D)CD cat AB tai S. Chung minh BC < 3.AS
cho tam giac ABC vuong tai A co AB=5cm,BC=10cm
a, Tinh do dai AC
b, ve duong pg BD cua tam giac ABD va goi E la hinh chieu cua D tren BC. Chung minh tam giac ABC=EBD va AE vuong goc voi BD
c, goi giao diem cua 2 duong thang ED va BA la F. chung minh tam giac ABC=AFC
d, Qua A ve duong thang // voi BC cat CF tai G. chung minh 3 diem B,D,G thang hang
Cho tam giac ABC can tai A ,đuong cao AH. bt AB=5cm, BC= 6cm
a) tinh đo dai cac đoan thang BH,AH
b) goi G la trong tam cua tam giac ABC, chung minh rang 3 Điem A, G, H thang hang
Cho tam giac ABC n tai A co duong cao AH
a/ Chung minh tam giac ABH = tam giac ACH va AH la tia phan giac cua goc BAC
b/ Cho BH = 8 cm ; AB = 10 cm . Tinh AH
c/ Goi E la trung diem cua AC va G la giao diem cua BE va AH . Tinh HG
d/ Ve Hx song song voi AC, Hx cat AB tai E . Chung minh C,G,E thang hang
( giup minh voi nhe THANH YOU )
Cho tam giac ABC vuonA , co AH la duog tai ng cao (H thuoc BC) va AM la tia phan giac cua goc HAC (M thuoc BC) . Ke MK vuong goc voi AC tai K . a,Chung minh rang AH = AK,BA = BM. b,Goi I la giao diem cua duong thang MK va duong thang AH . Chung minh rang AM vuong goc CI va KH song song C
Cho tam giac abc vuong tai a ke ah vuong goc voi bc tai h. Hoi a,chung minh tam giac abh bang tam giac ach , ve trung tuyen bm goi g la giao diem cua ah va bm cm g la trong tam abc c, cho ab= 30 bh=18 tinh ah ag d, tu h ke hc song song ac cm 3 diem cgd thang hang
cho tam giac ABC can tai A . Ve BH vuong goc voi AC (H thuoc AC) ,CK vuong goc voi AB(K thuoc AB) a/chung minh rang AH=AK b/ goi i la giao diem cua BH va CK .chung minh ^KAI=^HAI c/duong thang AC cat BC tai P .chung minh AI vuong goc voi BC tai P
cho tam giac abc co goc c+90 do=goca ve ah vuong goc bc duong thang vuong goc voi ab tai a cat bc tai d goi m la giao diem cua cac tia phan giac goc bah va adh chung minh goc bah=2c chung minh mavuong goc ac