! !! "#$%&'()%!*+!! !"#$%# && , /01023456 478 ,9:5;*3<010234 5647=0>=58 ,?@0+68 !'$()*+, /*0(1$ )*+, /*0 )*+, (1$ !&23456782$9 ,A+'B@)CB+)D. EFB1@+2GE8 *0(1$7824:2 !!2:2(2;#782/G. !<!#0;-=> !?/@ ,A<H3I&JK'LB@)C< @M'N8 ,A@M-.C010 2+C4OP3<HI&JK8 QN<3++C4O .M34C408 AEF0102+C 4OP3I&JK REF3'L8 AB C.D56 E,A@M'4@ M)D.<N3'L8 ,AST04U102+C 4OP3I&J-B+ GV ,W@M'B+)8 ,'5'B+)>8A'D >X))@)C8 2 B i ,AY('B+)/) 1 HS lên bảng, HS cả lớp làm bài vào vở bài tập. - HS nhận xét bài làm của bạn Ba igii Nối A với D, khi đó mảnh đất đợc chia thành 2 hình: Hình thang ABCD và hình tam giác ADE. Kẻ các đờng thẳng BM và NE vuông góc với AD. Ta có: BC = 30 m AD = 55m BM = 22m Diện tích h - 1 HS đọc đề bài trớc lớp. Bài giải !8 ,!'B@)CB+)='CBE.B+) <<Z)D.8 F $G/H-/I,AD>XG=<7 )=>[+E)8 8 §é dµi c¹nh BG lµ: 28 + 63 = 91 ( m ) DiÖn tÝch tam gi¸c BCG lµ: 91 x 30 : 2 = 1365 ( m 2 ) DiÖn tÝch cña h×nh tam gi¸c AEB lµ: 84 x 28 : 2 = 1176 ( m 2 ) DiÖn tÝch h×nh ch÷ nhËt ADGE lµ: 84 x 63 = 5292 ( m 2 ) DiÖn tÝch cña h×nh ABCD lµ 1365 + 1176 + 5292 = 7833 ( m 2 ) VËy diÖn tÝch cña m¶nh ®Êt lµ 7833 m 2 JKLB \8W@MLL ?](^D=:__<Z8 ,AG4-)0C=3)4-3()<*>68 ,"+4U)D. ) \\8^)` M<@O5Y=)-8 MAZ)D.='L8 \\\8'$()*+, /*0(1$ )*+, (1$)*+, /*0 CBE.<G)C8 CBE.[aZ'L8 4M+B4<*8 A*b5c55G <b(D=+ 68A"@M65P EB_6=U6 Bd@Y8 O.'L8 CBE.<G<<Z8 4Y<Ze)8 4@M)D.8 B+)f=_)8 I8&g T<GhP(f+4M ==if+0=6=3= j &8&+E!8E1) 8EF[,<G <@4)<G8 MT<*5473V "1<Gh5P(M=C+)=6 &Tk=B_8 Thfi)l.Dm4 <G<<Z8 <@4B)0C Bn8 <@)O+8 o8EFB+)D.0C8 &@@M)D.8 J.G5Y=B@)CB+ 8M_B4d<7?+= 48 M&Ga==Hj )8MJ+44M<E5P5* +gC+8 M"E.+S))@f=NC <S8 447=@l) i05622+^ 18 B+)f=_) B@)C 89M+3=`=j )8Z=+Qj )8 &o@@M)D.8 4)J3P <+^1<8 o8F $GH-/I D>X8 A74)pJ3Pp=E B+^1<5Bf[= B1<GB_he0C8 NBOPQRSNTO \8W@MLL 9:5;*<q?<rhP=<G=4if=<G<*8 ,AD?B+)D.8 ,?@N]GA18 \\8^)` M<@^)`O5Y=)-8 M'L=<Z8 \\\8'$()*+, /*0(1$ )*+, (1$)*+, /*0 &B@_)oo8 T7he==8 bl4@M)D.8 [.G=3)8 ;<?6f s76f t(6f &Y.D6f 1+6f8 bl4@M)D.8 CBE.4M+=;<B+) I8&g _)D.oo8 &8&+E !8E1)8 8EFB+)D.8 &! <@.)-<.G B+8 & @@M)D.8 EFr;ZlI<E ?+h0U.Zl&8Jo=u.G D.f=)B@)CB+ )8 CBE.[aD>X= 4@M)D.o8 bl=SB++F=P) 4G*+f<7;<?)C<1YNr 2+n6f8 CBE.<G)<<Z8 r4)<*8 CBE.D>X8 4Q5vw)D.8 )B@)CB+)8 &o @@M)D.8 C0f<*Z)D.oBf& P<E-)l4lf`.&4G *+47d8J/<fP2&= Q<G4<*5C%f<7;<? )C<1YNr2+n6f8 <ZO+=D>X=@_ <G4<*8 o8F $GH-/I D>X8 A7>[+B)=E_h_ 4Q<q?4-_h_l 2476f4if=<G4<*8 x[+E)r<GfX.)k N1h 8 7()%!*+!! 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