在线等!一道初一数学题!高手帮忙!要有过程!

来源:百度知道 编辑:UC知道 时间:2024/06/17 19:01:05
两直线AB,CD交于O,OE平分∠BOD,如果∠AOD比∠AOC=11比7.
1.求∠COE度数
2.若OF⊥OE,求∠COE

我没有图,所以不要找我要图,要用初一下的方法,要有过程,一些废话就不要说了。总而言之,不一定要对,但一定要快!!!
第二问打错了:
若OF⊥OE,求∠COF

∠AOD + ∠AOC = 180
∠AOD = 11n, ∠AOC = 7n
==> (11 + 7)n = 18n = 180
==> n = 10
==> ∠AOC = 70, ∠AOD = 110

∠AOC = ∠BOD = 2 * ∠BOE
==> ∠BOE = 35

∠BOC = ∠AOD = 110
==> ∠COE = ∠BOC + ∠BOE = 145

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若F和E在CD同侧,则∠COF = 180 - ∠DOF - ∠EOF = 180 - 35 - 90 = 55
若F和E在CD两侧,则∠COF = 180 - ∠DOF = 180 - (90 - ∠DOE) = 180 - (90 - 35) = 125

(1)∠AOD:∠AOC=11:7
∠AOD+∠AOC=180°
∠AOD=110 ° ∠AOC=70°
∠BOD=∠AOC=70°
∠COB=∠AOD=110°
OE平分∠BOD
∠BOE=∠DOE=35°
∠COE=∠COB+∠BOE=110°+35°=145°
(2)若OF⊥OE,求∠COE
∠COE与OF⊥OE没有关系啊

∠AOD比∠AOC=11比7
∠AOD+∠AOC=180
故:∠AOD=110,∠AOC=70
,∠BOD=∠AOC=70
OE平分∠BOD
∠DOE=∠BOE=∠DOB/2=35
∠COB=∠AOD=110
∠COE=∠COB+∠BOE=70+35=105

2.
OF⊥OE
∠FOB=90-∠BOE=90-35=55
∠COF=∠COB-∠FOB=110-55=55
或∠COF=180-55=125

1. ∠AOD=11x,∠AOC=7x,
7x+11