定义:把四边形的某些边向两方延长,其他各边有不在延长所得直线的同一旁,这样的四边形叫做凹四边形.如图1,四边形ABCD为凹四边形.
A. Is the man your father? B. No, I don't.
C. What are you going to be one day? D. What does he do?
E. Who's the man? F. Where does he work?
G. Does your father work in a car factory?
A:Hello. ____
B:Yes, he is my father.
A:____
B:He is an engineer.
B:He works in a car company. He likesdrawing pictures.
A:Do you like drawing pictures?
B:____ I like singing.
B:I'm going to be a singer one day.
The clothes in the wardrobe(衣柜). Don't put them on the bed.
∠ACB=∠BDC=45°,DC = 3 ,求: