a) ve doan thang pq=10 cm . ve duong trung truc cua doan thang pq 

 tren duong trung truc cua doan thang  pq lay diem m khong thuoc pq . qua diem m ve duong thang d\\ pq

ve doan thang PQ=10cm ve duong thang trung truc cua doan thang PQ 

tren duong thang trung truc cua doan thang PQ lay diem M ko thuoc PQ .Qua diem M lay ve duong thang dsong song vo PQ

Cho 1 doan thang AB dai 4cm.Ve duong thang d la duonbg trung truc cua doan thang AB,lay O thuoc d.Qua O ve doan thang OC=2cm sao cho OC vuong goc voi d.Qua O ve doan OD=1cm sao cho OD vuong goc voi d.Chung minh C,O,D thang hang.D co phai la trung truc cua doan thang CD ko?Vi sao?(Mik can ve hinh va loi giai nhe,minh ve hinh ko chac chan,mong cac ban giup do)

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

ve duong thang xy.Tren xy lay 2 diem I,B roi lay diem C sao cho I la trung diem cua doan thang BC. Lay diem D sao cho B la trung diem cua doan thang ID.

a) Co phai CD dai gap 3 lan IB khong?Vi sao?

b) Ve trung diem M cua IB. Vi sao diem M cung la trung diem cua CD?

cho tam giac abc vuong tai a, co ac = 9 bc = 24, duong trung truc cua bc cat duong thang ac tai d, cat bc tai m. tinh doan duong cd

Cho doan thang AB=4cm ve duong tron tam A ban kinh 3cm va duong tron tam B ban kinh 3cm cat nhau tai C va D .chung minh CD la duong trung truc cua AB. Viet ca GT va KL nhe

Cho tam giac ABC co AB=BC . Goi I la trung diem cua AB . Tren tia CI lay D sao cho D nam khac phia voi C so bo la doan thang AB

a/ c/m tam giac ADC=BDC

b/ suy  ra CD la duong thang trung truc cua AB

{ ko can ve hinh nhung viet ro gium minh cai cam on nhieu }

tren duong thang a lay 2 diem A va B sao cho AB=2cm lay diem C sao cho A la trung diem cua doan thang BC lay diem D sao cho B la trung diem cua doan thang AD a)tinh do dai doan thang CD   b) goi trung diem cua AB la M tim trung diem cua doan thang CD