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2024 届南宁市初中毕业班适应性测试
数学参考答案
一、选择题(本大题共12小题,每小题3分,共36分)
题号 1 2 3 4 5 6 7 8 9 10 11 12
答案
A B A C A B D A C B D C
二、填空题(本大题共6小题,每小题2分,共12分 )
1
13.x(x-5); 14.x≥3; 15. ; 16.(0,6); 17.25; 18.nm2.
3
三、解答题(本大题共72分)
19.(本题满分6分)
解:原式=9(1)+2,·····························3分
=-9+2,·····································4分
=-7.········································6分
20.(本题满分6分)
解:原式=a2 2abb2 2abb2,·············2分
=a2 4ab.································4分
1
当a=2,b=- 时,
4
1
原式=22 42( ),·····················5分
4
=4-2
=2.··········································6分
21.(本题满分10分)
(1)如图所示,CE即为所求;·····················5分
(2)证明:∵在Rt△ABC中,∠ACB=90°,∠A=40°,
∴∠B=90°-40°=50°.··················6分
又点D为AB中点,
∴CD=BD.·······························7分
(第21题图)
∴∠B=∠DCB=50° .·················8分
∵CE平分∠BCD,
1
∴∠BCE= ∠BCD=25°.··········· 9分
2
∴∠AEC=∠B+∠BCE=75°.········10分
数学参考答案 第1页(共4页)
{#{QQABAYCUggAoAIJAARhCQQ2QCAMQkBEACAoGhFAEIAAByAFABAA=}#}22.(本题满分10分)
(1)m=40,a=12,n%=40%;·················3分
(2)他的说法是错误的.···························· 4分
理由如下:
∵在参加测试的40名学生测试成绩中,排在最中间的两个分数都是85,
8585
∴中位数为 85.·····················6分
2
∵84<85,
∴有一半以上的同学成绩超过了84分.···7分
∴小邕的说法是错误的.
(3)解:500×(40%+30%)=350(人)············9分
答:估计本年级中食品安全意识良好的学生人数为350人.····················10分
23.(本题满分10分)
(1)证明:∵AB∥DE,
∴∠B=∠E.······································ 1分
又BF=CE,
∴BF+FC=CE+FC,即BC=EF.·············2分
在△ABC和△DEF中
ABDE
BE,·····································3分
BC EF
∴△ABC≌△DEF(SAS).···················4分
(2)解:连接AD交FC于点O,
∵△ABC≌△DEF,
∴AC=DF,∠ACB=∠DFE.················5分
∴AC∥DF.
∴四边形ACDF是平行四边形.
(第23题图)
又AF=FD,
∴四边形ACDF是菱形.·······················6分
1
∴AD⊥CF,OF=OC= FC=2.
2
在Rt△ACO中
∴AO AC2 OC2 ( 13)2 22 3,··7分
∴AD=2AO=6.··································8分
1 1
∴S = FCAD 6412.·····10分
四边形ACDF
2 2
数学参考答案 第2页(共4页)
{#{QQABAYCUggAoAIJAARhCQQ2QCAMQkBEACAoGhFAEIAAByAFABAA=}#}24.(本题满分10分)
(1)解:设团购群1《儒林外史》和《简爱》的单价分别是x元、y元;············1分
3x2y12220
由题意得: ,·····3分
4x3y288
x48
解得 .···························5分
y32
答:团购群1《儒林外史》和《简爱》的单价分别是48元、32元.············6分
(2)解:团购群1:(4832)150.784(0 元), ·······································7分
团购群2:7015105(0 元)
1050-40393(0 元),····8分
∵840<930,·································9分
∴选择团购群1购买更合算.············10分
25.(本题满分10分)
(1)证明:如图1,连接OC,·····················1分
∵OA=OB,CA=CB,
∴OC⊥AB.····································3分
又OC为半径,
∴AB是⊙O的切线.························4分
(2)解:设半径为R,
在Rt△OCB中,∠OCB=90°,BC= 1 AB=4, (第25题图1)
2
OB2 OC2 BC2,即R22 R242,
解得R=3,···································5分
∴OB=OE+BE=5.··························6分
方法一:如图2,过O作OM⊥EG于点M,
又OA=OB,AC=BC,
∴∠A=∠B.
又OF=OE,
∴∠F=∠OEF=∠BEG.
∴△AFG∽△BEG.··························7分
∴∠AGF=∠BGE=90°, (第25题图2)
FG AG AF 8
4.
EG BG BE 2
∴FG=4EG,AG=4GB.
∴AB=4GB+GB=8.
8
解得GB= .··································8分
5
2
8 6
∴EG BE2 BG2 22 .·············································9分
5 5
6 18
∴EF FGEG3EG3 .················································10分
5 5
数学参考答案 第3页(共4页)
{#{QQABAYCUggAoAIJAARhCQQ2QCAMQkBEACAoGhFAEIAAByAFABAA=}#}方法二:如图3,连接DE,
OD OE 3
∵∠DOE=∠AOB, ,
OA OB 5
∴△DOE∽△AOB.·························7分
DE OE 3
∴ .
AB OB 5
24
∴DE= .····································8分 (第25题图3)
5
∵DF是⊙O直径,
∴∠DEF=90°.·····························9分
2
24 18
∴EF DF2 DE2 62 .··········································10分
5 5
26.(本题满分10分)
(1)解:由题意可知,抛物线顶点为(2,2),经过B(0,1.2)
设抛物线的解析式为yax222···············································1分
将点B(0,1.2)代入,得1.2a0222,
1
解得 a .·············································································2分
5
1
∴抛物线的解析式为y x222.············································3分
5
(2)队伍排列时,最高的队员在正中间其位置的横坐标为2,
其余同学按照从高到低的顺序在其两侧对称排列.
身高为1.68与1.73的队员所在位置的横坐标分别为1.5与2.5,···············4分
身高为1.60的队员所在位置的横坐标分别为1与3;
∵1.8<2,
∴身高最高的队员可以通过.·····························································5分
1 1
由题意,把x1.5代入y x222中,得y 1.52221.95.
5 5
∵1.95>1.73>1.68,
∴可以通过.····································· ·············································6分
1 1
由题意,把x1代入y x222中,得y 12221.8.
5 5
∵1.8>1.60,
∴可以通过.····································· ·············································7分
综上所述,所有队员都可以通过.
1
(3)由题意,把y1.60代入 y x222中,
5
1
则1.6 x222.·····································································8分
5
解得x 2 2,x 2+ 2 (舍去).···················································9分
1 1
∵2 2>0.5,
∴最左边的跳绳队员与离他最近的甩绳队员之间距离的取值范围:
2 2<x≤1.································· ·············································10分
数学参考答案 第4页(共4页)
{#{QQABAYCUggAoAIJAARhCQQ2QCAMQkBEACAoGhFAEIAAByAFABAA=}#}