\(1+1\times2=1+2=3\)

`1+1 xx2 = 1 + ( 1xx2 ) = 1+ 2 = 3 `

Bán kính đường tròn là : \(R.R=78,5:3,14=25\)

Mà \(5\times5=25\)

\(\Rightarrow R=5\left(cm\right)\)

\(\Rightarrow d=R+R=5+5=10\left(cm\right)\)

đường kính hình tròn \(=\) đường chéo hinh vuông

Diện tích hình vuông \(ABCD\) là : \(2\times S_{ABD}=2\times\left(\dfrac{1}{2}\times5\times10\right)=50\left(cm^2\right)\)

Diện tích phần tô đậm là : \(78,5-50=28,5\left(cm^2\right)\)

các bn giải giúp mình với ah

Chiều cao là :

\(S_{xp}=2\times h\times\left(a+b\right)\\ \Rightarrow156=2\times h\times\left(8+5\right)\\ \Rightarrow156=26\times h\\ \Rightarrow h=6\left(cm\right)\)

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)

Vì `O` nằm giữa `M;N`

`=>OM+ON=MN`

`=>2+5=MN`

`=>MN=7(cm)`

Lời giải:

Từ điều kiện đề bài suy ra $O$ nằm giữa $M$ và $N$

$\Rightarrow MN=MO+NO=2+5=7$ (cm)

Vì Ox và Oy là hai tia đối nhau, điểm O nằm giữa hai điểm M và N nên ta có:

\(OM + ON = MN\)

\(2 + 5 = MN\)

⇒\(MN = 7 (cm)\)

Vậy độ dài đoạn thẳng MN là 7 cm.

9

a thấy tích trên có 201 thừa số mà mỗi thừa số có tận cùng là 9

nên tích trên có tận cùng là 9^201

ta có: 9^201=9^(4.50).9

vì 9^(4.50) có tận cùng là 1

nên tích trên có tận cùng là 1.9=9

tích trên có tận cùng là 9

9 nha