Nửa chu vi là : 280 : 2 = 140 ( m )

Chiều rộng là : ( 140 - 50 ) : 2 = 45 ( m )

Chiều dài là : 45 + 50 = 95 ( m )

Diện tích là : 95 x 45 = 4275 ( m² )

( Rồi ta vẽ hình như đầu bài trên bạn nhé! )

Nhìn vào hình vẽ ta thấy, diện tích hình vuông là : 45 x 45 = 2025 ( m² )

Diện tích phần HCN còn lại là : 4275 - 2025 = 2250 ( m² )

                                                                                                                                          Đáp số: 2250 m²

đề ra có số là 9,306

Radar is an electronic device that can “see” great distances (1)_____fog, rain, snow, cloud, and darkness. It can find and (2)_____locate missiles, aircraft, ships, cities, rainstorms, and mountains. Radar uses radio waves, (3)_____light waves, which the human eye uses in seeing. This makes it (4)_____for radar to locate many kinds of objects at (5)_____greater distances than the eye can see. Radar became an important military device during World War II. Today, networks of radar lookout stations guard the United States and Canada 24 hours a day against (6)_____missiles and airplanes. Patrol planes and ships (7)_____the oceans with radar for hostile ships and aircraft. Airports use radar to ()_____planes safety to earth in fog or storms. Ships use it to steer clear of other (59)_____or icebergs. Radar helps weathermen warn of (10)_____ hurricanes or tornadoes.

Sửa lỗi sai.

The chain of riders stations along the way were crucial to the success of the pony express

A B C D

1. It's important that she (remember)............ to take her medicine twice a day.

2. By this time next week, I (save)................. 400 dollars.

3. His roommate (always enter) ................. the room without knocking first, which annoys him a lot.

4. Nowadays children would prefer history (teach) ............ in more practical ways.

5. My boss is angry with me, I didn't do all the work that I (do)...... last week.

6. The man (rescue)......... had been in the sea for 10 hours.

7. You'd better (not come)............. to her office between 2 pm and 4 pm today. She (have)............ an office meeting then.

1. Her written work is excellent. She puts her ideas......... so well.

A. across B. forward C. on D. out

2.Do you think we'll find a solution....... this problem.

A. about B.to C. of D. with

3. " Could I just do it right now? " - " ..................... "

A. Yes, you could B. Not for me C. Yes, let's D. Why not? Go ahead

4. He goes to the restaurant now and ........

A. after B. here C. now D. then

5. Some people............. sports in order to keep fit, not because they like them.

A. train B. practice C. make D. do

6. I am sure he didn't break your vase........... purpose.

A. in B. with C. for D. on

7. My parents were so disappointed when I ........... college.

A. got out of B. fell out of C. dropped out of D. moved out of

8. ......... at his lessons, he couldn't catch up with his classmates.

A. Hardly as he worked B. Hard ad he worked C. Hard as he does D. Hard as he was

9. Our soccer team lost ........... three goals to nil.

A. with B. by C. to D. in