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
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cho hinh thang abcd (ab//cd) co bc = bd . goi h la trung diem cua cd. duong thang qua h va cat ac va ad lan luot tai e va f . cm goc dbf bang goc ebc
Cho tu giac abcd la hinh thang co day lon ab bang 9 cm day be cd= 3cm ad= 3cm va goc adc =120°. Goi m,n lan luot la trung diem cua ab va cd. Goi i la trung diem cua mn. Ci keo dai cat ab tai e. Chung minh tu giac amnd la hinh thang can.
Chung minh tu giac emcn la hinh chu nhat
Cho hinh thang vuong ABCD ( goc A bang goc D = 90 do) AB= 3cm, CD = 7cm,AD = 4cm
A) Tinh dien tich hinh thang ABCD
B) Goi M,N lan luot la trung diem cua AD,BC,H la hinh chieu cua N tren CD. Tinh dien tich tu giac MNHD
cho hinh thang ABCD(AB/CD) E,F lan luot la trung diem cuaAD va BC .goi G la giao diem cua EF va AC .biet rang AB = 6cm ;CD= 8cm .tinh đo dai cua EG va EF
cho hinh thang ABCD (AB//CD, AD khac BC). Goi E, F lan luot la trung diem cua cac duong cheo BD, AC va G la giao diem cua duoang thang qua E vuong goc voi AD va duong thang qua F vuong goc voi BC. CMR GD=GC
cho hinh thang can ABCD day nho AB day lon CD, AC cat BD tai O va goc AOB =60 do .goi M,N lan luot la hinh chieu cua B,C tren AC,BD; E la trung diem cua BC.CMR tam giac MNE deu
cho hinh chu nhat abcd co ab=2ad tren canh bc lay diem m duongt hang ef vuong goc am(e,f lan luot nam tren ab va cd duong phan giac dam cat cd tai k
chung minh ef=mb/2+dk
cho hinh thang abcd (ab//cd). 2 duong phan giac cua goc a va c cat nhau tai i. 2 duong phan giac cua goc b va c cat nhau tai i. Goi h la trung diem cua ad. k la trung diem cua bc biet ab=ad=10cm, bc =12cm,cd= 20 cm.Tinh hi,if,fa