1 n h rn c 9 n h I a A B , va BC h I a al n h dl nh B, d i n h C • Ba g 6c I a g 6 c dl n h A; g 6 c dl n h S; g 6 c al n h C D ucm g c a o c u a ta m g i a c I a OO( l n t h a n g ke t u mot dln h v[.]
1 nh rn c9 n h Ba • va Ia: AB, BC dl nh B, din h C h I a : al n h g 6c I a : g6c dln h A; g6c dln h S; g c al n h C Ducm g c a o c u a ta m g i a c I a OO(:l n t h a n g ke t u mot dln h va vuong g o c v6'i c� n h doi di� n (c� n h day) DQ d a i cua dliong ca o Ia chieu M¢t ta m g i a c c6 duang cao cao c u a ta m giac Ta m gi ac ABC c6: A H Ia chieu cao t u'ong ung voi c� n h day BC; Bl la chieu cao tuang c H A ung v6'i c9 n h AC; CK I a c h ieu ca o tuong U'n g v6'i c9 n h AB Ch u vi: P = a + b+c (P: ch u vi; a, b , c I a a(> dai ba c9 n h ta m g i a c) Di$n tich: S == AHxBC _ BixAC s _ 2 sX2 Aa y a = h- ; tro n g Ch e u ca o h = ; Cc;I n h u "' Ca c d� ng H1 n h ta m X a CKxA B , u Ao , h I a' c h 1eu cao tuong ling c9 n h a , A' ta m g ia c Hin h vu6ng (c6 m¢t g6c vu6ng) Hlnh (2 cgnh can nhau) Hlnh ta m gi a c cteu (3 cc;mh bang nhau) A rc h i m ed es Aschoo A RC H I M E D ES SCH O O L IL c A c o�NG sAt TAP A T in h c a c Bai yeu t o cua ta m g i a c D i e n ket q u a v a o (v6i a c h i e u ca o tlfon g U'n g cua c� n h do) � \ a I Bai I I i 25 cm · � - s 400cm - -· I , O,Sdm ! I l i l l f)i en ket q u a vao (v-a i ta m giac vu6ng) vuong C�n h g 6c vuong 2 rn l I cm2 _ 2,5 dm L d m2 _ ,2d m cm , Sdm 4d m - -·· dm2 Di�n tich tam qiac - '""··· ··· 8m l I 5d m 4d m I C� n h g6c 7cm 3,8m I l h I i , . I a ch i eu d a i m¢t C9 n h cua hl n h ta m g ia c v a h Ia _ .� 00 c m ·····�·�·········· Bai Tfnh di$n tfch tam giac/ biet d9 dai m¢t c�nh Ia 2cm va chieu cao tVdng U'ng Ia Scm Bai M9t tam b ien bao g iao thong hl n h ta m g iac c6 tong c9nh day va chieu cao tvang ung Ia 32m, C