如图,CD‖EF,∠C＋∠F=∠ABC,求证:AB‖GF

相关推荐

• 如图，E、F分别为直角三角形ABC的直角边AC和斜边AB的中点，沿EF将△AEF折起到△A′EF的位置，连接A′B、A′C，P为A′C的中点．（1）求证：EP∥平面A′FB；（2）求证：平面A′EC⊥平面A′BC；（3）求证：AA′⊥平面A′BC．
• 如图,已知BD是∠ABC的平分线,AB=BC.点D在射线BD上,PM⊥AD于M,PN⊥CD于N.求证PM=PN.拜托有谁做过这题,
• 如图所示,在△ABC中,M是BC的中心,E、F分别在AC,AB上,且ME⊥MF,试说明EF＜BF+CE
• 如图,已知AD=BC,AB=CD,O是BD中点,过O做直线交BA的延长线于E,交DC的延长线于F,求证OE=OF
• 已知,如图,AB=CD,AD=BC,O为BD中点,过O作直线分别于DA,BC的延长线交于E,F.求证OE=OF
• △ABC是等边三角形,BD=CD,∠BDC=120°,EF分别为AB、AC上的点,∠EDF=60°.求证：ED=BE+CF
• 如图所示,等边三角形ABC中,D、E分别在AB、AC上,且BD=AE,CD、BE交于O,DF⊥BE于F.求证：OD＝2OF八年级上第二单元的.没有图,见谅=急用、
• 在等边三角形ABC中,点E,D分别在AB,AC上,且BD=AE,CD交BE于点O,DF垂直BE,点F为垂足求证：∠ABE=∠BCD求证：OD=2OF第一问 ：∵AB=BC,∠A=∠ABC,AE=BD∴△EAB≌△DBC∴∠ABE=∠BCD第二问：∠ADC=∠ABE+∠DOB=∠BCD+∠ABC∴∠DOB=∠ABC=60°又DF⊥BO所以OD=2OF
• 已知：如图,在等边三角形ABC中,点D,E分别在AB,AC上,且DB=AE,CD交BE于点O,DF⊥BE,点F为垂足,1）求证：∠ABE=∠BCD:2)求证：OD=2OF
• 将三角形纸片（△ABC）按如图所示的方式折叠,使点B落在边AC上,记为点B′,折痕为EF．已知AB＝AC＝3,BC＝4,若以点B′,F,C为顶点的三角形与△ABC相似,那么BF的长度是 ．答案我已找到：12/7或2
• 请帮我看看这段英文写得对不对.At the time of noon lunch,Miss Li told me that she is very tired to take care for her sick daughter last week.I think to raise a child is bittersweet.You feel happy when your baby first call you mum,but when he/she is sick you will be very worry about it.As you know,everything is not always the same better as imagination,but just for the reason that life can be called life.
• 已知：如图,在△ABC中,AB=AC,EF是△ABC的中位线,延长AB到D,使BD=AB,连接CD.求证：CE=1/2 CD