user-avatar
hoanghoan20011
2 năm trước
Cho tam giác AOB có AB = 18cm; OA =12cm; OB=9cm. Trên tia đối của tia OB lấy điểm D sao cho OD = 3cm .Qua D kẻ đường thẳng song song với AB cắt tia AO ở C. Gọi F là giao điểm của AD và BC a) Tính độ dài OC; CB b) Chứng minh rằng FA.BC=FC.AD c) Qua O kẻ đường thẳng song song với AB cắt AD và BC lần lượt tại M và N. Cm: OM = ON. Vẽ mình hình thôi ko cần làm
Thích Trả lời Chia sẻ

Các câu hỏi liên quan

1). Choose the word which has a different sound in the part underlined. (0,75pt) 1.A.develop B. economic C. enormous D. become 2. A. archaeology B. chemist C. chat room D. character 2). Choose the word which has a different stress pattern from the others. (0,25pt) 3. A. unhappy B. oversleep C unwise D. impatient 4. A. invent B. support C. transform D. breakdown 5. A. expensive B. ability C. nationality D. unhealthy II. Choose A, B, C, D for each gap in the following sentences. (2pts) 1. Which TV programme ………… at 9p.m tomorrow? A.did you watch B.will you watch C. will you be watching D. do you watch 2. He tried very hard ……………..the test yesterday. A. to finish B. finish C. finishing D. finished 3. He said he ……. very hard and that was the key….. his success. A. work/ to B. worked/ to C. work/ for D. worked/ for 4.If you don’t understand body language, …………….breakdown may happen. A. communicate B. communicative C. communication D. communicating 5.I don’t mind ………….. A. wait B. waiting C. to wait D. waited 6. Scientists say that people………. longer in the future. A. will live B. live C. are living D. would live 7. This job would be…………..without the help of a computer. A. possible B. impossible C. wise D. unwise 8.Future homes will take advantages ….robots to do chores. A. at B.of C. in D. on III. Give the correct form of the following verbs: ( 2 pts) 1. 1. They ………………………(play) football at 10a.m tomorrow morning. 2. Radio waves…………………….. ( discover ) by Heinrich Hertz. 3,Scientists are planning ……………( send) people to explore Mars. 4. Future homes ……………(locate) on the ocean.. 5. I think robots ………….( help) us do many difficult jobs. IV. Give the correct form of the word ( 1pt). 1. Thomas Edison was one of the greatest…………..of the world. ( invent) ). ......................... 2. There are a lot of…………….differences . culture ) ....................... 3. …………….. pollution has risen day by day. ( environment ) ....................... 4. There have been major new ………….. in space reseach. ( develop ) ........................ 5. Sugar is not …………… food. ( health) V. Complete the following passage then answer the questions: (1.0point) hard known interest telephone Alexander Graham Bell is widely …(1) as the inventor of the first telephone.He was born on March 3rd,1847 in Edinburgh,Scotland.When he was 23,Bell emigrated to Canada with his parents and the next year moved to the United States to teach deaf-mute children.He took great ..(2)…. in transmitting the human voice.With his colleague Thomas Watson, Bell worked very …(3)……….. on the experimentation to invent devices such as the harmonic telegraph( used to send multiple messages overa single write ) and phonautograph( used to draw the shape of the sound waves).The first …(4)…………… communication was said to have happened between Bell and Watson in 1876 while Bell was at one end of the line , and Watson worked on the telephone in another room. The first transmitted words were,” Mr Watson , come here I want to see you.” 1.Who is Alexander Graham Bell?...................................................................................................... 2. When did he move to Canada?..................................................................................................... 3. What was he interested in ?..................................................................................................... 4. What was the first telephone communication ?............................................................................ VII. Rewrite the following sentences without changing their original meanings.(1 pt) 1. Nam said “I am told to be at school before 7 o’clock” ………………………...……………………………………………………………………… 2. Thu said “All the students will have a meeting next week” ……………………………….……………………………………………………………… 3. The teacher said “All the homework must be done carefully” …………………………………………….…………………………………………………… 4. Her father said to her “You can go to the movie with your friend” ………………………………………………..……………………………………………… 5. “ I am doing an experiment now”. He said ……………………………………………..…………………………………………

1)Excuse me ! _____ for a phone book . Is there one here A is looking B are looking C am looking D looking 2) what _____ happen if yon come late for the meeting tomorrow A will be B would be C will D would 3) If there were no gravity , water ______ never run downhill A would B will C won`t D would`t 4) tom let me _______his car yerterday A to drive B driving C drive D driven 5) tom and i ______ close friends since we were at class 6 A has been B was C have been D were 6) I`m not n a hurry . I don`t mind ________ A wait B waiting C to wait D waited 7) I wish I had enough money ________ a new bicycle A buy B to buy C buying D bought 8) this morning I bought _________ newspaper and _______ umbrella A a/a B an/an C a/an D an/a 9) If you know english , yon can ________ with people from the english -- speaking world easily A communication B communicate C communicated D communicating 10) Susan is ______ in learning enghlish A interested B interesting C interest D interests

2018 © Loga - Không Ngừng Sáng Tạo - Bùng Cháy Đam Mê
Loga Team