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Cho tam giác ABC vuông tại A, đường cao AH. Khi đó ta có hệ thức
HA2 = HB.HC
Hay “Trong tam giác vuông, bình phương đường cao ứng với cạnh huyền bằng Tích hai hình chiếu của hai cạnh góc vuông trên cạnh huyền”
Đáp án cần chọn là: B
Tâm của các đường tròn có bán kính 1cm tiếp xúc ngoài với đường tròn (O; 3cm) nằm trên đường tròn (O; 4cm).
Tâm của các đường tròn có bán kính 1cm tiếp xúc trong với đường tròn (O; 3cm) năm trên đường tròn (O; 2cm).
1. The schoolboys were _____excited______ to go to the match between their school and the nearby one. (excite)
2. Many workers are _____disppointed______ to receive the pay when they start the first job.(disappoint)
3. To tell the truth, I was ___amused______ to read the funny stories written by my classmate.(amuse)
4. All of us got ___shocked_____ to hear of the accident happening to our close friend, Henry. (shock)
5. Nowadays no one is _____free_____ to do what he wants if it does harm to the community. (freedom)
6. My pet dog is _____cased?_____ to please, so I can give it anything edible. (case)
7. The _____farmers____ in the village are is->are sad to hear that there will be no rain in the next two weeks. (farm)
8. Green Peace is an ___organization_____ keen to protect the environment (organize)
9. The scientist is sure to find something _____useful_____ from his experiment.(use)
11. Mike failed his physics final ____exam____ and had to sit it again. (examine)
12. Their teachers used to punish them by ____making_____ them stay behind after school. (make)
13. Everyone agrees that a good _____education______ is important. (educate)
14. This book has a very ____interesting______ introduction. (interest)
15. We find listening ___comprehension_____ tests rather difficult. (comprehend)
16. Ben went on to be a very ____successful______ student at university. (success)
17. You should pay more ____attention______ in class if you want to make progress. (attend)
18. Before you begin the exam paper, please read the instructions ____carefully____ (care)
19. In our country, children start ____secondary______ school at 12 years old.(second)
20. Ben missed the test because of his ___absence_____last Monday. (absent)
21. You must be ___careful_______ when you open that door. (care)
22. We'll live a happier and _____healthier_____ life if we keep our environment clean.(health)
23. You are talking complete _____sensibly______ (sense)
25. Some ____environmental______ groups have declared a boycott of tourism on the island. (environment)
26. Air _____pollution_______ can cause illness and even death. (pollute)
27. We're very _______excited___ about our holiday. (excite)
28. Jackson canceled the concert to the great ______disappointment___ (disappoint)
29. Customers made a formal ____complaint_____ treated (complain)
30. She declined his invitation because of the ____impoliteness_____ of his fans (polite)
31. That old man told me an ____amazing_____ story (amaze)
32. Gasoline fumes ____pollute(tham khảo c32)____ the city air (pollution)
33. I think the careless drivers should be fined ____heavily____ (heavy)
34. Many people are concerned about the pollution of the ____environment_____ (environmental)
35. The seaside has a ____healthy_____ climate (health)
Nếu điểm M thuộc đường thẳng ax + by = c thì tọa độ (xo; yo) của điểm M là một nghiệm của phương trình ax + by = c.
Nếu điểm M thuộc đường thẳng ax + by = c thì tọa độ ( x 0 ; y 0 ) của điểm M là một nghiệm của phương trình ax + by = c.
A
A