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第 5 章 相交线与平行线 名师检测卷
1. D 2. C 3. A 4. B 5. A 6. A 7. B 8. B 9. D 10. B
11. 同位角相等ꎬ两直线平行 12. 14 13. 8° 14. 115° 15. ∠1 +∠2 -∠3 = 180°
16. 解:(1)如图所示ꎬAE 就是所求作的直线.
(2)如图所示ꎬCD 就是所求作的直线.
(3)如图所示ꎬBF 就是所求作的直线.
17. 解:AB∥CDꎬ理由如下.
∵ EM∥FNꎬ∴ ∠FEM =∠EFNꎬ又∵ EM 平分∠BEFꎬFN 平分∠CFEꎬ
∴ ∠FEB = 2∠FEMꎬ∠EFC = 2∠EFNꎬ∴ ∠FEB =∠EFCꎬ∴ AB∥CD.
18. 解:设∠AOC = 4xꎬ则∠AOD = 5xꎬ∵ ∠AOC +∠AOD = 180°ꎬ∴ 4x + 5x = 180°ꎬ
解得 x = 20°ꎬ∴ ∠AOC = 4x = 80°ꎬ∴ ∠DOB =∠AOC = 80°. ∵ OE⊥ABꎬ
∴ ∠BOE = 90°ꎬ∴ ∠DOE =∠BOE - ∠DOB = 90° - 80° = 10°ꎬ又∵ OF 平分∠DOBꎬ
∴ ∠DOF = 12 ∠DOB =
1
2 × 80° = 40°ꎬ
∴ ∠EOF =∠DOE +∠DOF = 10° + 40° = 50°.
19. 解:(1)由题意得∠FAB = 45°ꎬ∵ AF∥BEꎬ∴ ∠ABE = ∠FAB = 45°ꎬ∵ ∠EBC = 80°ꎬ
∴ ∠ABC =∠EBC -∠ABE = 80° - 45° = 35°.
(2)D 处应在 C 处的南偏西 45°方向. 理由如下:∵ CG∥BEꎬ∴ ∠GCB = ∠EBC = 80°ꎬ
∵ CD∥ABꎬ∴ ∠BCD = ∠ABC = 35°ꎬ∴ ∠GCD = ∠GCB - ∠BCD = 80° - 35° = 45°.
∴ D 处应在 C 处在南偏西 45°方向.
20. 解:(1)DG∥AB. 理由如下.
∵ AD∥EFꎬ∴ ∠2 +∠BAD =180°ꎬ又∵ ∠1 +∠2 =180°ꎬ∴ ∠1 =∠BADꎬ∴ DG∥AB.
(2)∵ DG 是∠ADC 的平分线ꎬ∴ ∠GDC =∠1 = 30°ꎬ又∵ DG∥ABꎬ
∴ ∠B =∠GDC = 30°.
21. 解:(1)ES∥TH. 理由如下:由题意ꎬ知∠AST =∠BSEꎬ∠DTH =∠CTSꎬ∵ AB∥CDꎬ
∴ ∠AST = ∠CTSꎬ∴ ∠AST = ∠BSE = ∠DTH = ∠CTSꎬ∴ ∠TSE = 180° - ∠AST -
∠BSE = 180° -∠DTH -∠CTS =∠STHꎬ∴ ES∥TH.
(2)EM∥NP. 理由如下:由题意ꎬ知∠AMN = ∠BMEꎬ∠ANM = ∠DNPꎬ∴ ∠NME =
180° - 2∠AMNꎬ∠MNP = 180° - 2∠ANMꎬ∵ ∠AMN 与∠ANM 互余ꎬ∴ ∠AMN +
∠ANM = 90°ꎬ∴ ∠NME + ∠MNP = 360° - 2∠AMN - 2∠ANM = 360° - 180° = 180°ꎬ
∴ EM∥NP.
22. 解:(1)90°
(2)∠GEF =∠BFE + 180° -∠CGE.
解:如图 2ꎬ过点 E 作 EH∥ABꎬ∴ ∠FEH =∠BFE(两直线平行ꎬ内错角相等)ꎬ
∵ AB∥CDꎬEH∥AB(辅助线的作法)ꎬ∴ EH∥CD(平行于同一直线的两条直线平
行)ꎬ∴ HEG = 180° - ∠CGE(两直线平行ꎬ同旁内角互补)ꎬ∴ ∠GEF = ∠HEG +
∠FEH =∠BFE + 180° -∠CGE.
(3)∠GPQ + 12 ∠GEF = 90°. 理由如下:如图 3ꎬ∵ FQ 平分∠BFEꎬGP 平分∠CGEꎬ
∴ ∠BFQ = 12 ∠BFEꎬ ∠CGP =
1
2 ∠CGEꎬ ∵ 180° - ∠GMF = 180° - ∠GPQ -
∠PFMꎬAB∥CDꎬ∴ ∠GPQ = ∠GMF - ∠PFM = ∠CGP - ∠BFQꎬ由(2)知∠GEF =
∠BFE + 180° - ∠CGEꎬ∴ ∠GPQ + 12 ∠GEF =
1
2 ∠CGE -
1
2 ∠BFE +
1
2 ∠GEF =
1
2 × 180° = 90°.
23. 解:(1)∵ AM∥BNꎬ∴ ∠ABN +∠A = 180°.
∵ ∠A = 60°ꎬ∴ ∠ABN = 120°ꎬ∴ ∠ABP +∠PBN = 120°.
∵ BC 平分∠ABPꎬBD 平分∠PBNꎬ∴ ∠ABP = 2∠CBPꎬ∠PBN = 2∠PBDꎬ
∴ 2∠CBP + 2∠DBP =