de hoc sinh gioi huyen toan 6 nam 2018 2019 phong gddt nam nhun lai chau

h."-NHI]N PHONG GD&DT NAM DE THI CHQN HOC SINH GIOI CAP HUYEN Nim hgc 20t8-2019 M6n thi: Torln Ngdy thi: 1310112019 Thoi gian.ldm bdi: 150 phrit DE THI CHiNH THUC (Di thi gim 0ltrans) (Kh6ng k€ thdi gian phdt d€) DA bni CAu 1: (4,0 tli6m) Thuc hi6n phdp tinh a) 155.155 - 155.41 114 b) 2to s5 + 210.26 28.27 c) 134- {150:50+ [120: 4+25-(12+ l8)]] d) 100: {2s0: [450-( 4.53 -22.2s)]\ CAu 2: (4,0 tli6m) Tim x, bi5t a) zs9 =+ 888.1112>g.lll2 =2223 >3332 Do d6 222333 >333222 vd z3n Ta c6: 32n:132;n= 23n=123yn:gn 0,25 0,25 0,25 32n d 9n Vi9>8+9n>8"(VineN-) Nen 32n > 23n 2t3 0,25 0,25 0,2s 0,25 05 BIA o C Vi B ld trung di€m cria OA n6n a Oe: (cm) !=!=z 22 Ta c6 A nim gifra O vd C, mir B nim gita O vd A < OA ( < 6), n€n B nim gita O vd C +OB + BC: OC hay +BC:9 vi OB 05 +BC:9-3:6(cm) 05 I Di€m A nim gita y16 n6n 661- ag :9 - 6: (cm) Hay + AC :9 =AC L4i c6: B ld trung diiim crla OA n6n ne (6,0d) b =AB: AC:3 (cm) (l) : OC : $ = ! =:1cm) 22 0,5 0,5 Vi I ld trung di6m cria do4n thing OC n6n I nim gita O vd C, md A vd B thuQc tia d6i chung g5c I n€n di6m I nim gita hai