2024 年秋学期初三数学期中考试参考答案与评分标准
一、选择题(本大题共 10 小题,,每小题 3 分,共 30 分.)
1.B 2.C 3.D 4.C 5.B 6.C 7.D 8.B 9.A 10.B
二、填空题(本大题共 8小题,每小题 3分,共 24分.)
1
11. 12 8. 13.1:16 14. 10
5 3
2 5 4 5 8 5
15.20 16.60° 17.4 5 18. , ,
5 5 5
三、解答题(本大题共 9 小题,共 96 分.)
19. (本题满分 16分)
5
(1) (x 2)2
25
, x 2 ········································································· 2分
4 2
1
x 91 , x2 ······················································································· 4分2 2
(2) (m 1)2 4(m 1) 0, (m 1)(m 1 4) 0 ············································· 2分
m 1 0或m 3 0,m1 1,m2 3 ····················································4分
(3) t 2 2t 15 0 ······················································································· 1分
(t 3)(t 5) 0, t 3 0或 t 5 0 ························································ 2分
t1 3, t2 5 ·······················································································4分
(4)a=2,b=-4,c=1, ( 4)2 4 2 1 8 0,······································2分
x 2 2 ······························································································ 4分
2
20. (本题满分 10分)
(1)∵四边形 ABCD是正方形,∴∠B=∠C=90°,∴∠AEB+∠BAE=90°············2分
∵AE⊥EF ∴∠AEF=90°∴∠AEB+∠CEF=90°······································3分
∴∠BAE=∠CEF ··················································································· 4分
∴ △ABE∽△ECF··················································································· 5分
(2)∵BE=3,EC=7,∴BC=3+7=10,···························································6分
∵四边形 ABCD是正方形,∴AB=BC=10····················································7分
∵△ABE∽△ECF ∴ AB BE ,10 3 ····················································· 9分
CE CF 7 CF
∴CF 21= .························································································· 10分
10
21.(本题满分 10分)
(1)200,36··································································································4分
(2) ·········································································8分
1
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46
(3)2000× =460(名),答:估计最喜欢“E乒乓球”的人数为 460名.········· 10分
200
22. (本题满分 10分)
1 =( 2k)2( )∵ 4 k (k 1)=4k 2 4k 2 4k=4k>0 ,解得 k>0··············3分
又 k 1 0即 k 1··············································································· 4分
∴ k 0且 1························································································· 5分
(2)∵0<k<5且 k 1,∴整数 k的值为 2,3,4,·············································6分
3x2 8x 4 0 2当 k=4时,方程为 - = ,解得 x1=2,x2= ,·····························8分
3
当 k=3或 2时,此时方程没有整数解.
综上所述,k的值为 4.··········································································· 10分
23. (本题满分 10分)
(1)证明:连接 OC,∵PC与半圆相切于点 C,∴∠OCD=90°,··························1分
∴∠DCE+∠ACO=90°,········································································· 2分
∵OA=OC,∴∠A=∠ACO,····································································3分
∵OD⊥AB ∴∠AOE=90°∴∠A+∠AEO=90°,······································· 4分
∴∠DCE=∠DEC=∠AEO,∴DC=DE·······················································5分
(2)解:∵OA=2OE,∴设 OE=x,AO=2x,
∴EF=OF﹣OE=x,∴DE=DC=x+3,OD=2x+3,
∵OC2+CD2=OD2,∴(2x)2+(x+3)2=(2x+3)2,·····································6分
∴x=6或 x=0(不合题意舍去),·································································7分
∴OD=15,OC=OB=12,CD=9,
∵∠DOP=∠OCD=∠DOP=90°,∴∠D+∠DOC=∠DOC+∠COP=90°,
∴∠D=∠COP,∴△CDO∽△COP,···························································· 8分
∴OD CD ,∴ 15 9 ,∴OP=20,···························································9分
OP OC OP 12
∴BP=OP OB=8···················································································· 10分
24. (本题满分 10分)
(1)∵2x+y=80,∴y= 2x+80,
∵S=xy,∴S=x( 2x+80)= 2x2+80x;·················································· 2分
(2)∵y≤42,∴ 2x+80≤42,∴x≥19,∴19≤x<40,······································· 4分
当 S=750时, 2x2+80x=750,
x2 40x+375=0,(x 25)(x 15)=0,∴x=25,········································6分
∴当 x=25m时,矩形实验田的面积 S能达到 750m2;
(3)当 S=850时, 2x2+80x=850,即 x2 40x+425=0
∵ =( 40)2﹣4 1 425= 100 0 ∴x无解, 面积 S不能达到 850m2················ 8分
∵S= 2x2+80x 2 2,即 2x 80x S 0,由 =( 80)﹣4 2 S 0
∴ S 800 ∴S最大值 800m2, 此时 x=20m.···············································10分
2
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25 (本题满分 10分)
(1)①作 AC的中垂线,交射线 AQ于点 O,·······················································2分
以 O为圆心,OA为半径作⊙O交射线 AQ于点 O.·····································4分
②作∠CBQ的平分线交 CP于 M.······························································ 6分
(2) 265 ···································································································10分
2
26. (本题满分 10分)
(1)取 AC的中点 G,连接 EG
∵∠ACB=90°,CB=2,CA=4∴ AB 22 42 2 5 ································ 1分
∵E是 AB的中点∴EG= 1 BC=1,EG∥AC,AE= 1 AB= 5
2 2
∴∠EGA=∠ACB=90°∵AE= 5 AD ∴AD=1,CD=3··································· 2分
∵AG=GC=2,∴DG=AG AD=1=EG
∴∠EDG=∠DEG=45°∴∠EDA=135°······················································· 3分
由翻折得∠ADE=∠FDE=135°,AD=AF=1
∴∠CDF=∠EDF ∠EDG=135° 45°=90°,·············································4分
∴CF DF 2 CD2 12 32 10 ···························································· 5分
(2)过 E作 EH⊥AC于 H,设 EF与 AC相交于 M,设 AD=x, AE 5x,
由翻折得 DF=AD=x,∠ADE=∠FDE,则∠AHE=∠ACB=90°,
又∵∠A=∠A,∴△AHE∽△ACB,∴ EH AH AE ,
BC AC AB
∵CB=2,CA=4, AB 2 5,∴ EH AH 5x ,
2 4 2 5
∴EH=x, AH 2x,则 DH=AH AD=x=EH,
∴Rt△EHD是等腰直角三角形,···································································· 6分
∴∠HDE=∠HED=45°,则∠ADE=∠EDF=135°,
∴∠FDM=135° 45°=90°,···································································7分
∵∠FDM=∠EHM=90°,∠DMF=∠HME,DF=EH
∴△FDM≌△EHM(AAS),
1
∴DM MH x,CM AC AD DM 4
3
x,
2 2
∴ S S S 1CM EH 1CM DF 1 3 (4 x) x 2 3 (4 x) x,·········8分 CEF CME CMF 2 2 2 2 2
S 1 1 ,········································· 9分 BEC S ABC S AEC 4 2 4 x 4 2 x2 2
4 4
∴ (4 3 x)x 2(4 2x),解得 x1 ,x2=4(舍去),则 AD ·······················10分2 3 3
3
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27. (本题满分 10分)
(1)OM+ON=2AP························································································· 2分
(2)①当 M在线段 AO上时,如图,延长 NM、PA交于点 G.
由(1)知 OM+ON=2AP,设 OM=2x,则 ON=5x,OA=AP=3.5x.
∴AM=AO OM=1.5x,
∵∠MON=∠MAG=90°,∠OMN=∠AMG,
∴△MON∽△MAG,∴OM ON ,
2x 5x
AM AG 1.5x AG
∴AG=3.75x································································································4分
∵AP∥OB,∴△ONF∽△PGF,
∴OF ON 5x 20 ,∴ OP 49 ;··············································· 6分
PF PG 3.5x 3.75x 29 OF 20
②当 M在 AO的延长线上时,如图,过 P作 PC⊥OB于 C,并延长交 MN于 G.
∵∠AOB=90°,PA⊥OA ∴四边形 OAPC是矩形,
∵点 P在∠AOB的平分线上∴∠AOP=∠APO=45°∴PA=OA
∴四边形 OAPC是正方形
∴OA=AP=PC=OC,∠APC=90°,PC∥AO,
∵PN⊥PM,∠APM=∠CPN=90° ∠MPC,
又∵∠A=∠PCN=90°,AP=CP,∴△APM≌△CPN,∴AM=CN,
∴ON OM=OC CN OM=AO AM OM=2AO,
∵OM=2x,ON=5x,∴AO=1.5x,CN=AM=3.5x,
∵PC∥AO,∴△CGN∽△OMN,
∴ CG CN ,即 CG 3.5x ,∴CG=1.4x,······················································· 8分
OM ON 2x 5x
∵PC∥AO,∴△OMF∽△PGF,
∴OF OM 2x 20 ,∴ OP 9 ; 综上, OP的值为 49 或 9 .········· 10分
PF PG 1.5x 1.4x 29 OF 20 OF 20 20
4
{#{QQABTYiAggCAAAJAAAhCEQEiCAKQkhEACYgGQFAAsAABSQFABAA=}#}宜兴市2024年秋学期期中考试
九年级数学试题
2024.11
本试卷分试题和答题卡两部分,所有答案一律写在答题卡上
考试时间为120分钟,试卷满分150分,
注意事项:
1.答卷前,考生务必用0.5毫米黑色墨水签字笔将自己的姓名、班级、考试号填写在答题卡的
相应位置上,并认真核对姓名、班级、考试号是否与本人的相符合,
2.答选择题必须用2B铅笔将答题卡上对应题目中的选项标号涂黑,如需改动,请用橡皮擦干
净后,再选涂其他答案.答非选择题必须用0.5毫米黑色墨水签字笔作答,写在答题卡上各题目指
定区域内相应的位置,在其他位置答题一律无效
3.作图必须用2B铅笔作答.
4.卷中除要求近似计算的结果取近似值外,其他均应给出精确结果
一、选择题(本大题共10小题,每小题3分,共30分,在每小题所给出的四个选项中只有一项是正
确的,请用2B铅笔把答题卡上相应的选项标号涂黑)
1.一元二次方程x2=x的解是
…(▲)
A.x1=x2=1
B.x1=1,x2=0
C.x1=x2=0
D.x1=-1,x2=0
2.已知(m-3)x2-7+2024x-2024=0是关于x的一元二次方程,则m的值为…(▲)
A.3
B.0
C.-3
D.±3
3.下列网格中各个小正方形的边长均为1,阴影部分图形分别记作甲、乙、丙、丁,其中是相似形的
为…((▲)
甲
丙
A.甲和乙
B.乙和丁
C.甲和丙
D.甲和丁
4.已知⊙0的直径是6,点P到圆心0的距离是6,则点P与⊙0的位置关系是…(▲
A.点P在⊙0内
B.点P在⊙0上
C.点P在⊙0外
D.点P是圆心
5.两年前生产1千克甲种药品的成本为80元,随着生产技术的进步,现在生产1千克甲种药品的
成本为60元.设甲种药品成本的年平均下降率为x,下列方程正确的是…(▲)
A.80(1-x2)=60
B.80(1-x)2=60
C.80(1-x)=60
D.80(1-2x)=60
6.小亮在计算正数a的平方时,误算成a与2的积,求得的答案比正确答案小1,则a=
A.1
B.5-1
C.2+1
D.1或2+1
7.宽与长的比是5,'的矩形叫黄金矩形,黄金矩形给我们以协调的美感,世界各国许多著名建筑
2
为取得最佳的视觉效果,都采用了黄金矩形的设计.已知四边形ABCD是黄金矩形(AB
A.3
B.2
C.1
D.0
一九年级数学试卷共6页第1页一