cho hinh vuong ABCD. tren canh BC lay diem M tren canh CD lay diem N sao cho CM=DN, AN cat DM tai P. a) cmr tam giac ADN dong dang tam giac DCM b)CM tu giac ABMP va tu giac CMPN noi tiep c)AM va BN cat tai Q. CM diem Q nam tren duong tron ngoai tiep tu giac

cho hinh tam giac ABC co gocA la goc vuong va canh AB=6 cm,canh AC = 9 cm tren canh AB lay diem M va N sao cho AM=MN=NB,tren canhAC lay diem K va H sao cho AK=KH=KC.tinh dien tich hinh tu giac MNHK

Cho hinh chu nhat ABCD, lay diem M tren canh CD sao cho MD bang ¹/₃ CD, lay diem N tren canh BC sao cho BN bang ¹/₃ BC. Doan thang AC cat BM tai P, doan thang AN cat BM tai Q. Tinh dien tich hinh tu giac PQNC biet dien tich tam giac APQ la 216 cm².
 

Cho hinh vuong ABCD. Tren canh AB; BC; CD; DA lần luot lay cac diem M; N; P; Q sao cho AM = 1/3 AB; BN =1/3 BC; CP =1/3 CD; DQ =1/3 DA. Noi AN cat BP va DM tai G va K. Noi CQ cat BP va DM tai H va I. Tinh dien tich hinh tu giac GKHI biet dien tich hinh vuong ABCD bang 900cm2 

Cho tam giac ABC can tai A. Tren canh BC lay hai diem M va N cac duong thang AM va AN cat duong tron tam O ngoai tiep tam giac ABC theo thu tu tai E vaF .CM:                   TU GIAC MNFE NOI TIEP

cho hinh vuong ABCD co canh a . M di chuyen tren DC (M khac C va D) . Lay N thuoc BC sao cho goc MAN =45 do BD cat AM va AN tai E va F 

a) CMR tam giac ABF dong dang voi tam giac AMC

b) goc AFM=goc AEN =90 do

c) CM chu vi tam giac CMN khong thay doi khi M di chuyen tren CD

Cho hinh vuong ABCD co canh bang a. Goi M la diem tren canh BC, N la diem tren canh CD sao cho BM=CN. Cac doan thang AM va BN cat nhau tai H

a)CM: tu giac AHND, MHNC la tu giac noi tiep

b)khi BM=a/4. Tinh dien tich hinh tron ngoai tiep tu giac AHND theo a

c)tinh gia tri nho nhat do dai doan MN theo a

Cho tam giac ABC vuong tai A lay diem D bat ky thuoc canh BC tu D ke duong vuong goc vs AB tai E vuong goc vs tai F

a? cm tam giac BED dong dang tam giac BAC

B? cm DB/DC = FA/FC

C/ tren tia doi ED lay diem K sao cho EK=ED. goi H la giao diem cua KC va EF . Cm tam giac HKE dong dang tam giac HFC

d/ CM DH // BK

cho tam giac vuong ABC co canh goc vuong AB = 40 cm . tren canh AC lay mot diem M sao cho AM bang 1/4 canh AC .tu M ke duong thang vuong goc voi AC va cat canh BC tai diem N . tinh do dai doan thang MN