Hinh thang ABCD co AB//CD co E la trung diem cua BC goc AED= 90 do
Chung Minh Rang DE la tia phan giac cua goc D
Cho tu giac ABCD biet so do cua cac goc A ,B,C,D ti le thuan voi5,8,13,10 .a, Tinh so do cac goc cua tu giac ABCD . b, Keo dai hai canh AB va DC cat nhau o E , keo dai hai canh AD va BC cat nhau o F . Hai tia phan giac cua cac goc AED va goc AFB cat nhau o O . phan giac cua goc AFB cat cac canh CD va AB tai M va N . Chung minh O la trung diem cua doan MN
CAC BAN GIUP MINH VOI MINH CAN GAP
BAI 1 : cho hinh thang ABCD khong co goc vuong biet tong do dai 2 canh day AB va CD thi bang do dai canh ben AD cmr cac duong phan gaic trong goc A vs goc D di qua trung diem E cua BC
Bai 2 : cho hinh thang ABCD co AB//CD cmr neu CD = AD + BC thi cac duong phan giac cua cac goc A va B cat nhau tai 1 diem thuoc canh day CD
Lam giup mink vs mink dang gap lam . THANKS
Bai 1: Cho hinh tam giac ABC co goc A = 90. Goi M la trung diem cua BC. Ke MN vuong goc voi
AB, MP vuong goc voi AC
a) Tu giac ABMP la hinh gi? Vi sao?
b) Tu giac ANMP la hinh gi? Vi sao'
) Tinh do dai doan NP biet BC = 8cm
d) Tam giac ABC can them dieu kien gi de ANMP la hinh vuong?
cho hthang abcd ab//cd co e thuoc bc sao cho de la tia pgiac goc d va goc aed=90 do. goi k la giao diem cua 2 duong thang ae và cd
a. cm tam giac adk can
b. biet ad=10cm, ae=6cm tinh s_abcd
Cho hinh thang can ABCD (AB//CD) co DB la tia phan giac cua goc D ;DB vuong goc BC biet AB =4cm .Tinh chu vi hinh thang
Cho hinh thang can abcd co day bc,ad.Goi m,n,p,q theo thu tu la trung diem cua ab, bc,cd,da
a)cmr:MP la phan giac goc qmn
b)tim dieu kien cua hinh thang abcd doi voi 2 duong cheo de goc mnq bang 45 do
c)cmr:co them dieu kien do thi hinh thang can abcdco duong cao +duong trung binh cua no
bai 1 cho hinh thang can abcd va ab<cd ke ac duong cao ah va bk ua hinh thang goi m la trung diem ad va n la trung diem bc m va n lan luot cat bd tai e va ac tai d biet ab =4cm cd = 10 cm tinh ef
bai2 cho tam giac abc can tai a co ab>bc 2 dg trung tuyen ad va be duong thang qua e // bc cat ab tai f goi i va k lan luot la trung diem bf va ce biey ik = 7,5 ad= 12 tinh bcc va tinh chi vi hinh thang
bai 3cho tu giac abcd co goc a = goc d , goc b + goc c = 180 goi m , n theo thu tu la trung diem bc va ad a) cm abd la hinh vuong b) cm am = dm c) cho ab = 3cm ad= 4m bc= 5cm tinh mn
GIUP MINK VS
THANKS NHIEUUUUUUUUUU LAM
BAI 1
Cho tam giac ABC co BC = 8cm,cac trung tuyen BD , CE .Goi M , N theo thu tu la trung diem cua BE va CD .Goi giao diem cua MN voi BD,CE theo thu tu la I,K
a,Tinh do dai MN
b, CMR;MI = IK = KN
BAI 2
Cho hinh thang ABCD(AB//CD). Cac duong fan giac cua cac goc ngoai tai dinh A va D cat nhau tai M.Cac duong fan giac cua cac goc ngoai tai dinh B va C cat nhau tai N
a,CMR ;MN//CD
b,Tinh chu vi hinh thang ABCD biet MN =4cm
NHO CAC BAN GIUP VOI NHA