问题
填空题
已知a＞b，如果a2-b2，2ab是三角形较小的两条边，那么当第三边等于______时，这个三角形是直角三角形．
答案
设第三边等于x时，这个三角形是直角三角形，
则x=
=a2+b2．(a2-b2)2+(2ab)2
故答案为：a2+b2．
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已知a＞b，如果a2-b2，2ab是三角形较小的两条边，那么当第三边等于______时，这个三角形是直角三角形．
设第三边等于x时，这个三角形是直角三角形，
则x=
=a2+b2．(a2-b2)2+(2ab)2
故答案为：a2+b2．
| 完型填空 | |||
| In the past, people didn't use stamps. They had to pay money when they received letters. Rowland Hill, a schoolmaster in England was the first 1 using stamps. He thought it 2 much easier for people to use 3 . They could go to the nearby 4 to buy stamps and put them on envelopes(信封) 5 they 6 letters. The post office only put seals(印章) 7 the stamps so that people could not use the stamps 8 . In this way, the post office 9 send postmen to collect(收) money. It only needed 10 postmen to deliver(投递) letters. The government finally accepted(接受) the good idea. | |||
| ( )1. A. to think ( )2. A. could be ( )3. A. a stamp ( )4. A. a shop ( )5. A. after ( )6. A. sent ( )7. A. in ( )8. A. again ( )9. A. need not to ( )10.A. few | B. thinking B. will be B. stamps B. school B. before B. send B. over B. too B. didn't need to B. fewer | C. to think of C. is C. stamp C. village C. in C. to send C. on C. either C. needed not to C. many | D. think about D. was D. stampes D. post office D. with D. sended D. above D. also D. didn't need D. much |