Câu 30,31 giúp mình với mấy bạn

Cho tam giác abc có ba góc nhọn và AB < AC các đường cao AD, BE, CF cắt nhau tại H 1) Chứng minh : ACD ~ BCE . 2) Chứng minh : HB.HE = HC.HF. 3) Cho AD = 12 cm ; BD = 5 cm ; CD = 9 cm. Tính AB và HC.

Phần tự luận ạ ! mong achi viết càng dài càng hay càng tốt ạ ! nhớ là đừng copy mạng hay bất cứ thứ gì ạ cô giáo e sẽ bt ạ . e cảm ơn. hứa vote 5 * ạ

Change the sentences into the passive voice (chuyển sang câu bị động) 1.I will turn off the lights when leaving a room or going to bed. The lights: 2.Wind power will offer a great deal of energy next century. A great deal of energy: 3.we will use sources of energy more effectively for our future. Sources of energy: Giúp mik với mai nộp r

Complete the second sentence so that it has a similar meaning to the first. 1.l usually stayed up late to watch football matches last year,but now l don't. l used: 2.There were some frees in the fiend,but now there aren't any. There uesd: 3.Linda doesn't live with her parents any more Linda used: 4.He is not a poor man any more, but he becomes a rich businessman. He used: 5.they didn't often go to the cinema every Sunday last year. They didn't use: 6.My hair now is much longet than that in the past. In the past my hair used: 7.I don't have time ti collect stamps as when I was in primary school. I used: 8.did you often go to the beach when you lived in nha trang. Did you use: Ai giúp mik với hứa cho 5 sao

cho khối chóp s abcd có thể tích là 2a^3/3 SA vuông góc mặt đáy đáy là tam giác vuôn tại C biết SC=2a BC=a khi đó khoảng cách từ A đến SBC giải dùm mình

2.My father________( make always) excuses when i feel going to the cinema. 3.His students________(not, speak) German in class. 4.His students_________(not,be) six years old. 5.john________(wornk) in a supermarket. 6.The flowers________(phone) his father on sundays. 7.Danny________(phone) his father on sundays. 8.I_______(not,know) what you mean. 9.My husband and his colleague_______golf whenever they are not too busy.(play) 10.John always_____on time for meetings (arrive) 11.Barbara usually_______dinner for her husband after work.(cook).

Qua bài thơ " Tức cảnh pác bó " hãy viết một đoạn văn tổng phân hợp khoảng 10 đến 12 câu làm rõ phong thái ung dung lạc quan luôn vượt lên trên hoàn cảnh của Bác.Trong đoạn văn có sử dụng một câu nghi vấn và một trợ từ (gạch chân và chú thích rõ)

II. Complete the following sentences with the correct form of the verbs in the table listen provide scatter build travel 11. Debris from collapsed buildings was ______ across the whole area. 12. Many countries have ______ food and other material aid to the hurricane victims. 13. Mary didn't use ______ when her teachers were speaking. 14. Can we ______ to Korea by car? 15. Ten new houses ______ in the town every year.

Find the word which has a different sound in the part underlined 1.A.lazy B.date C.hate D.car 2.A.said B.wati C.taste D.paid 3.A.safety B.waste C.taste D.chat 4.A.security B.belt C.let D.centre 5.A.head B.seat C.heavy D.weather