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a, Xét \(\Delta\)ABC có: AB2 + AC2 = 62 + 4,52 = 56,25 (cm2)
BC2 = 7,52 = 56,25 (cm2)
AB2 + AC2 = BC2 vậy tam giác ABC vuông tại A (đpcm)
SinC = 6 : 7,5 =0,8 ⇒ \(\widehat{C}\) = 53,130 ⇒ \(\widehat{B}\) = 900 - 53,130 = 36,870
b, Dựng hình chữ nhật ABCD, chiều cao AH, DK, và đường thẳng d đi qua D song song với BC như hình vẽ ta có
SABC = SBDC ⇒ AH = DK
Lây 1 điểm bất M kỳ di động trên đường thẳng d ta có:
SBDC = SMBC (vì hai tam giác có chiều cao bằng nhau và chung cạnh đáy BC)
⇒ SABC = SMBC
Kết luận khi M di động trên đường thẳng d thì diện tích tam giác MBC luôn bằng diện tích tam giác ABC
Tìm từ đồng nghĩa
37. Once you have finish reading, you can go on with your work.
A: continue doing
B: continue to do
C: keep do
D: keep to do
38. The doctor wanted to examine the test results with her patient.
A: go over
B: up
C: go on
D: go out
39. The local meeting is on this weekend. Please put it down in your diary.
A: make a note
B: made a note
C: have made a note
D: to make a note
40. You don't need the light on in here. Press the switch, please!
A: turn on
B: turn down
C: turn off
D: turn up
41. My grandfather has recovered form the illness.
A: get over
B: got over
C: to get over
D: getting over
42. She spent her chilhood in a small village in the south.
A: grew up
B: grow up
C: grown up
D: to grow up
43. We are really expecting to see you again pleasure.
A: looking forward to
B: look up
C: look for
D: look after
37. One you have finish reading, you can go on with your work.
A: continue doing
B: continue to do
C: keep do
D: keep to do
38. The doctor wanted to examine the test results with her patient.
A: go over
B: up
C: go on
D: go out
39. The local meeting is on this weekend. Please put it down in your diary.
A: make a note
B: made a note
C: have made a note
D: to make a note
40. You don't need the light on in here. Press the switch, please!
A: turn on
B: turn down
C: turn off
D: turn up
41. My grandfather has recovered form the illness.
A: get over
B: got over
C: to get over
D: getting over
42. She spent her chilhood in a small village in the south.
A: grew up
B: grow up
C: grown up
D: to grow up
43. We are really expecting to see you again pleasure.
A: looking forward to
B: look up
C: look for
D: look after
Hue, ________________________, attracts thousands of tourists every year.
A. which was recognized by UNESCO as a World Heritage Site in 1993.
C. where was recognized by UNESCO as a World Heritage Site in 1993.
III: Sắp xếp các từ đã cho thành câu hoàn chỉnh.
1. museum / me / the / it’s / to / interesting / go / to / for.
____it's interesting for me to go to the museum
2. dangerous / play / It’s / for / to / children / knife / with.
____it's dangerous for children to play with knife
3. sure / he / my / stolen / I / that / am / has / bike.
___i am sure that he has stolen my bike
IV: Viết lại câu sao cho nghĩa không thay đổi.
1. Learning English is no difficult for me.
→ It is not difficult to learn English_____________________________________________________________________________
2. Jim was very confident when he said that he was the best.
→ Jim was very confident to_say that he was the best___________________________________________________________
3. Peter received a letter from his foreign friend yesterday. He was very happy about it.
→ Peter was very happy to receive a letter from his foreign friend yesterday____________________________________________
4. I can’t come to your party this weekend. I’m afraid.
→ I am afraid_that i can't come to your party this weekend______________________________________________________________________
5. Doing gardening is not as easy as it looks.
→ It is not_easy to do garden_________________________________________________________________________
6. I had no difficulty in making the last decision.
→ It was not _difficult to make the last decision_______________________________________________________________________
7. I think Peter is very happy. He has won a lottery.
→ I think Peter is very happy that__he has won a lottery______________________________________________________
8. You were so lucky. You ran into a famous singer =) you were so lucky to ran into the famous singer
→ You were so lucky to_______________________________________________________________
nhớ chấm cuối câu (một số thầy cô khó tính không thấy có chấm ở cuối câu là không cho điểm đâu)
Vì \(AM\perp AH\left(gt\right)\)(1)
và \(BC\perp AH\left(gt\right)\)(2)
Từ(1) và (2)
\(\Rightarrow AM//BC\)(T/c )
Mà \(EF//BC\)(* )
Do \(\widehat{AEF}=\widehat{ABC}\)(do vị trí đồng vị )'
\(\Rightarrow AH\perp EF\)(*)
Mà \(AM\perp AH\left(gt\right)\)(** )
Từ (*) và (** )
\(\Rightarrow AM\perp EF\)
( đpcm)
1. Were people building robots hundreds years ago?
=> Yes,they were
2. Whose robots chose the next king- Egyptian robots or Greek ones?
=> It's Egyptian robots
3. Why wasn’t the female robot popular?
=> Beacause people didn’t need robots to work, they had lots of slaves.
4. What kind of musical instrument could mechanical robots play?
=> Mechanical robots could play the flute