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sok_linh


1.cho hinh chop s.abcd co day' la\ hinh\ thang vuong tai. A va D. AB = AD = a , CD= 2a. SD vuong goc' voi' day'. Goi. E la trung diem? cua? CD. Trong mp ( SCD ) ke? duong thang vuong goc' voi' SC cat' SC tai. K. Chung minh 6 diem s,a,d,b,e,k cung\ nam\ tren mo^t. ma)t. ca^u\?
Co giao' e huong' dan~ la tim 1 duong ma\ Cac' diem? Nhjn duong do' duoi' 1 goc' 90. Nhung e tim mai~ ko ra duong\ nao\ phu\ hop. Cac' bac' giup e ! Thank
2.Trong mat phang? Amfa, cho duong\ tron\ duong\ kinh' AA', du*ng. tam giac' ABC biet' AB = 3a, AC = 2a, goc' BAC = 60 do^. Tren duong\ thang? denta vuong goc' voi' mat. phang? amfa tai. diem? A lay' diem? S du*ng. AH vuong goc' voi' SB, AK vuong goc voi' SC. Chung' minh khi S chay. tre^n duong\ denta thi\ diem? A,K,H,B,C luon nam\ tre^n 1 ma)t. ca^u\
Co giao' e huong' dan~ la tim 1 duong ma\ Cac' diem? Nhjn duong do' duoi' 1 goc' 90. Nhung e tim mai~ ko ra duong\ nao\ phu\ hop. Cac' bac' giup e ! Thank
2.Trong mat phang? Amfa, cho duong\ tron\ duong\ kinh' AA', du*ng. tam giac' ABC biet' AB = 3a, AC = 2a, goc' BAC = 60 do^. Tren duong\ thang? denta vuong goc' voi' mat. phang? amfa tai. diem? A lay' diem? S du*ng. AH vuong goc' voi' SB, AK vuong goc voi' SC. Chung' minh khi S chay. tre^n duong\ denta thi\ diem? A,K,H,B,C luon nam\ tre^n 1 ma)t. ca^u\