VẼ HÌNH THÔI NHÉ ( THÍCH THÌ LÀM HẾT CX ĐC ) Bài 4 : Cho tam giác ABC cân tại A ( Góc A < 90 độ ) ; các đường cao BD ; CE ( D thuộc AC ; E thuộc AB ) cắt nhau tại H . a) Chứng minh tam giác ABD = tam giác ACE b) Tam giác BHC là tam giác j ? Vì sao ? c) So sánh HB và HD ? d) Trên tia đối của tia EH lấy điểm N sao cho NH < HC ; trên tia đối của tia DH lấy điểm M sao cho MH = NH . Chứng minh các đường thẳng BN ; AH ; CM đồng quy

em hãy xác định 60 độ c tương ứng với bao nhiêu độ F

Cho tam giác ABC có đường cao AH và góc BAH=2.góc C. Tia phân giác cáu góc Abc cắt AC tại E, tia phân giác cảu góc BAH cát BE tại I a: Chứng minh góc AIE=Góc AEI b: Kẽ IH vuông góc AB tại K; EF vuông góc với AH tại F.Chứng minh AK=EF c:Chứng minh AK+KI=AH

Chứng minh A=2/3.4/5.6/7...98/99 > 1/10

Cho đường tròn (O) , đường kính BC , A là một điểm nằm trên đường tròn sao cho dây AB bé hơn dây AC.Trên đoạn OC lấy điểm điểm D (D khác O,C).Từ D kẻ thẳng vuông góc với BC ,đường thẳng này cắt hai đường thẳng BA và AC lần lượt tại E và F. a)CM các tứ giác ABDF b)Tiếp tuyến tại A của đường tròn (o) cắt đường thẳng EF tại M. CM Δ MAE cân C) EC cắt đường tròn (O) tại J .CM ba điểm B,F, J thẳng hàng Vẽ hình thôi nha ko cần giải nha

1)There are a lot of people ______ voluntarily work in remote and mountainous areas nowadays. A. which B. whom C. who D. whose 2)The ground is dry and we haven’t had any _________ for months. It’s a real drought. A. rains B. rain C. rained D. raining 3)You can’t enter this website without a password. A. get access B. stop C. connect D. exit 4)When you put on clothing or make-up; you place it on your body in order to wear it. A. wash up B. take off C. look after D. get on 5)“I won’t come back to this place again next year.” - the man said. A. The man said he wouldn’t come back to that place again next year. B. The man said he wouldn’t come back to this place again the next year. C. The man said he wouldn’t come back to that place again the following year. D. The man said he wouldn’t come back to this place again in following year. 6)The hotel wasn’t very nice; however, we enjoyed our holiday. A. Although the hotel was not very nice, we enjoyed our holiday. B. However nice the hotel was, we didn’t enjoy our holiday. C. Although the hotel was not very nice but we enjoyed our holiday. D. The hotel wasn’t very nice; therefore, we didn’t enjoy our holiday.

Mark the letter A, B, C or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions. Maths and English are compulsory subjects on this course A. separated B. difficult C. effective D. required

*Có những chất rắn sau: FeO, P2O5, Ba(OH)2, NaNO3. Thuốc thử được chọn để phân biệt các chất trên là: A. dung dịch H2SO4, giấy quỳ tím. B. H2O, giấy quỳ tím. C. dung dịch NaOH, giấy quỳ tím. D. dung dịch HCl, giấy quỳ

20 Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions. The doctor advised him to stop _________ because it’s quite harmful to his health. A. smoke B. to smoke C. to smoking D. smoking 21 Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions. My grandparents used _________ in a small village in the north of Viet Nam. A. to living B. live C. to live D. living 22 Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions. There are a lot of people ______ voluntarily work in remote and mountainous areas nowadays. A. whose B. whom C. who D. which 23 Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions. Sending emails is an ______ way to communicate with other people. A. interested B. happy C. effective D. dangerous 24 Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions. The ground is dry and we haven’t had any _________ for months. It’s a real drought. A. rain B. rains C. rained D. raining 25 Mark the letter A, B, C or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions. The English summer course will start in May 9th and finish in August. A. in August B. will C. The English summer D. in May 9th 26 Mark the letter A, B, C or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions. My mother says she used writing a diary when she was young. A. was B. when C. writing D. says

Mark the letter A, B, C or D on your answer sheet to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions. When you put on clothing or make-up; you place it on your body in order to wear it. A. look after B. take off C. wash up D. get on