Cho tam giác ABC vuông tại A, biết AB = 3cm, BC = 5cm. a) Giải tam giác vuông ABC. (số đo góc làm tròn đến độ). b) Từ C kẻ đường thẳng vuông góc với BC, đường thẳng này cắt đường thẳng BA tại D. Tính độ dài các đoạn thẳng AD, CD. c) Gọi E, F lần lượt là hình chiếu của A trên BC và CD. Chứng minh: CF.CD = CE.CB. Làm giúp em với ạ em cảm ơn

giải giúp mình với mình đang cần gấp

Đốt cháy hoàn toàn a gam S rồi cho sản phẩm sục qua 200 ml dung dịch NaOH bM thu được dung dịch X. Chia X làm hai phần bằng nhau. + Phần 1 cho tác dụng với dd CaCl2 dư thấy xuất hiện c gam kết tủa. + Phần 2 tác dụng với dung dịch nước vôi trong dư thấy xuất hiện d gam kết tủa. Biết d > c. Tìm biểu thức quan hệ giữa a và b

Complete the telephone conversation between two friends. What does Jennifer say to Lily?For questions 1-4, mark the correct letter A-H on your answer sheet. Lily:Hi Jennifer, it will be lovely to see you on Friday. Jennifer: (0)…..B…………………… Lily:What time is your train? Jennifer: (1)…………………………. Lily: OK. I’ll meet you. Would you like to go out that evening? Jennifer: (2)…………………………. Lily: If you want to. Then on Saturday we can go to the new shopping centre. Jennifer: (3)…………………………. Lily: And in the evening we can go to Oliver’s party. Jennifer: (4)…………………………. Lily: Oh anything. It doesn’t matter. Jennifer: (5)…………………………. Lily:Yes. It's a good place for a party. See you Friday, then. A. I have to go home at 6 o’clock. B. Yes, I haven’t seen you for so long. C. I've heard it's really big. D. Is he still living in the same house? E. How long will we stay with him there? F. I think I’ll be tired. Shall we just stay at home? G. Great! What should I bring to wear? H. It should arrive early afternoon.

Đúng như dự tính ban đầu Nát mất cái tóc :") Ai gảnh sửa tóc với ạ :") Vẽ anime/ semi :33 Màu nhóa Digi càng tốt Thanks

Trình bày cahcs tách riêng từng chất trong các hỗn hợp sau:(1) bột sắt,vụn gỗ,vụn đồng.(2) tách đường ra khỏi hỗn hợp đường và tinh bột

Bài 4: Cho tam giác ADC vuông tại A có đường cao AH. Biết góc B= 65°, AH=3cm. a) Tính độ dài AD. b) Trên nửa mặt phẳng bờ DC chứa điểm A, vẽ tia Cx song song với AD. Trên Cx lấy điểm B sao cho CB = DA. Tính: khoảng cách từ B đến AD; độ dài đoạn BD và diện tích tam giác ABD. giải giúp mình với mình đang cần gấp

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help meeeeeee đọc và tóm tắt hộ mình nha T_T mình cần gấp lắm rồi Introduction When the sun comes out after it rains, run outside. You may see a rainbow in the sky. Rainbows are tricks made by light. We can see them, but we can't touch them or walk around them. They seem to move away when we try to get close to them. Science can explain how rainbows happen. Where and When Rainbows Appear Look around the next time you see a rainbow. The Sun will be shining from behind you. There will be rain in front of you, where you'll see the rainbow. We usually see a rainbow as a half-circle. It actually forms a full circle . From the ground , we can only see the top half. How Rainbows Form Years ago, a French scientist studied rainbows. He found that to see a rainbow , you must be in the right spot. Rainbows in Myths and Tales • Vikings said a rainbow bridge linked their gods to Earth. • In Ireland , people tell fairy tales about gold hidden at the ends of rainbows . Elves guard these pots of gold. •The Hindu god Indra is shown using a rainbow as an archer's bow to shoot lightning arrows. Knowing how light moves helps explain rainbows . Think of running on land. Now think of trying to run through water. You will move more slowly through water because it is thicker than air. In the same way , light moves faster through air than through water. As the light moves through water , it slows down and bends. Rainbows form when water drops meet sunlight. The light bends when it goes into each drop. Then it reflects, or bounces , off the back of each drop. The light bends again as it leaves the drop. This happens in millions of water drops at once , making the colors of a rainbow. The Colors of the Rainbow Sunlight is made up of many colors Water drops split the sunlight into different colors. Splitting light makes a rainbow. You have to be in the right spot to see a rainbow. Each water drop reflects colored light at a slightly different angle. The colors of the rainbow always appear in the same order. The name ROY G. BIV can help you remember the seven main They are red , orange , yellow , green , blue , indigo, and violet. Make Your Own Rainbow 1. Fill a clear glass about three - quarters full of water. 2. Place the glass where sunlight can pass through it. 3. Hold a white piece of paper . Let the light shine through the water onto the paper . Move the paper around until you find a rainbow. 4. Use colored pencils to mark the different colors on the paper. How many can you see ? What order are they in? Conclusion Rain stops and the Sun comes out. A beautiful rainbow sweeps across the sky. Most people find it hard not to stop and stare when a rainbow appears. Science explains how rainbows form. Still , a rainbow is always a magical sight to see .

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