第3个回答 2011-02-16
1解:
因为,OE是∠AOC的平分线,OF是∠BOD的角平分线
所以,角AOE=角EOC=1/2角AOC;角BOF=角FOD=1/2角BOD
因为,角AOC+角COD+角DOB=180°(平角)
所以,角EOF=角COD+角EOC+角FOD=角COD+1/2角AOC+1/2角BOD
=角COD+1/2(角AOC+角BOD)
=角COD+1/2(180°—角COD)
=120+1/2(180-120)
=150°
2 解:
AOE=COE=a BOF=FOD=b
AOB=AOE+COE+COD+BOF+FOD=180
2a+120+2b=180
a+b=30
EOF=EOC+COD+DOF=a+120+b=30+120=150