bài toán cm vuông góc

T

tunglam_95_01

Goi M N K I lan luot la trung diem cua cac doan DC CB BA AD
+)ta co tam giac SNI can tai S,0la trung diem IN =>SO vuong voi IN (1)
+)Ta co tam giac SKB can tai S,Ola trung diem KM=> SO vuong voi KM (2)
+)KM dao IN =0. (3)
+)KM,IN thuoc (ABCD) (4)
Tu (1)(2)(3)(4)=> SO vuong voi (ABCD) hay hinh chieu cua S trung O=>(dpcm)
 
You must log in or register to reply here.
Top Bottom