已知∠AOB=70°,∠COD=30°,OE,OF分别平分∠AOC,∠BOD(1)绕O旋转∠COD,当射线OC,OD在∠AOB内部时,求∠EOF.(2)绕O旋转∠COD,当射线OC在∠AOB外时,求∠EOF
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/28 17:51:40
![已知∠AOB=70°,∠COD=30°,OE,OF分别平分∠AOC,∠BOD(1)绕O旋转∠COD,当射线OC,OD在∠AOB内部时,求∠EOF.(2)绕O旋转∠COD,当射线OC在∠AOB外时,求∠EOF](/uploads/image/z/12557658-66-8.jpg?t=%E5%B7%B2%E7%9F%A5%E2%88%A0AOB%3D70%C2%B0%2C%E2%88%A0COD%3D30%C2%B0%2COE%2COF%E5%88%86%E5%88%AB%E5%B9%B3%E5%88%86%E2%88%A0AOC%2C%E2%88%A0BOD%281%29%E7%BB%95O%E6%97%8B%E8%BD%AC%E2%88%A0COD%2C%E5%BD%93%E5%B0%84%E7%BA%BFOC%2COD%E5%9C%A8%E2%88%A0AOB%E5%86%85%E9%83%A8%E6%97%B6%2C%E6%B1%82%E2%88%A0EOF.%EF%BC%882%EF%BC%89%E7%BB%95O%E6%97%8B%E8%BD%AC%E2%88%A0COD%2C%E5%BD%93%E5%B0%84%E7%BA%BFOC%E5%9C%A8%E2%88%A0AOB%E5%A4%96%E6%97%B6%2C%E6%B1%82%E2%88%A0EOF)
已知∠AOB=70°,∠COD=30°,OE,OF分别平分∠AOC,∠BOD(1)绕O旋转∠COD,当射线OC,OD在∠AOB内部时,求∠EOF.(2)绕O旋转∠COD,当射线OC在∠AOB外时,求∠EOF
已知∠AOB=70°,∠COD=30°,OE,OF分别平分∠AOC,∠BOD
(1)绕O旋转∠COD,当射线OC,OD在∠AOB内部时,求∠EOF.
(2)绕O旋转∠COD,当射线OC在∠AOB外时,求∠EOF
已知∠AOB=70°,∠COD=30°,OE,OF分别平分∠AOC,∠BOD(1)绕O旋转∠COD,当射线OC,OD在∠AOB内部时,求∠EOF.(2)绕O旋转∠COD,当射线OC在∠AOB外时,求∠EOF
(1)
∠EOF=∠EOC+∠COD+∠DOF=1/2∠AOC+1/2∠BOD+∠COD
=1/2(∠AOB-∠COD)+∠COD
=1/2(∠AOB+∠COD)
=1/2(70°+30°)=50°
(2)
∠EOF=∠EOA+∠AOD+∠DOE=1/2∠AOC+∠AOD+1/2∠DOB
=1/2(∠AOC+2∠AOD+∠DOB)
=1/2(∠AOC+∠AOD +∠AOD+∠DOB)
=1/2(∠COD+∠AOB)
=1/2(30°+70°)=50°
1)
∠EOF=∠EOC+∠COD+∠DOF=1/2∠AOC+1/2∠BOD+∠COD
=1/2(∠AOB-∠COD)+∠COD
=1/2(∠AOB+∠COD)
=1/2(70°+30°)=50°
(2)
∠EOF=∠EOA+∠AOD+∠DOE=1/2∠AOC+∠AOD+1/2∠DOB
全部展开
1)
∠EOF=∠EOC+∠COD+∠DOF=1/2∠AOC+1/2∠BOD+∠COD
=1/2(∠AOB-∠COD)+∠COD
=1/2(∠AOB+∠COD)
=1/2(70°+30°)=50°
(2)
∠EOF=∠EOA+∠AOD+∠DOE=1/2∠AOC+∠AOD+1/2∠DOB
=1/2(∠AOC+2∠AOD+∠DOB)
=1/2(∠AOC+∠AOD +∠AOD+∠DOB)
=1/2(∠COD+∠AOB)
=1/2(30°+70°)=50° 分给我吧
收起