问题
填空题
如果两圆相切，圆心距为7.5cm，一个圆的半径为4cm，则另一个圆的半径是______cm．
答案
当两圆外切时，
则圆心距等于两圆半径之和，此时另一个圆的半径是7.5-4=3.5（cm）；
当两圆内切时，
圆心距等于两圆半径之差，则另一个圆的半径是7.5+4=11.5（cm）．
故答案为：3.5cm或11.5．
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如果两圆相切，圆心距为7.5cm，一个圆的半径为4cm，则另一个圆的半径是______cm．
当两圆外切时，
则圆心距等于两圆半径之和，此时另一个圆的半径是7.5-4=3.5（cm）；
当两圆内切时，
圆心距等于两圆半径之差，则另一个圆的半径是7.5+4=11.5（cm）．
故答案为：3.5cm或11.5．
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| It was Monday morning. Cathy left home early that day because she was going to 1 a new job in Manhattan. She was only 18 and this was her first 2 . When she got to the bus stop, she saw so many people waiting there that she almost 3 a passing taxi. Later she was 4 that she had waited for the bus because the traffic was so heavy that even a taxi would not have 5 much earlier. As it was, she was only few minutes late! She took the elevator to the eighth 6 and went to the office where she had been interviewed (面试) by Mr. Samson two weeks 7 . This was the man she was going to work for. She knocked on the door lightly and waited, but there was no 8 ! Just then she heard the sound of a 9 voice coming from the next office. She opened the door and looked 10 . There was Mr. Samson, speaking 11 to all the other people in the office. He suddenly 12 around and left the room. Later in the day, Cathy found out 13 had happened. Because Mr Samson lived forty miles away in Westchester, he had to take the train to work and would usually arrive at the office 14 nine thirty. This morning, however, he happened to catch an earlier train, and when he arrived at 15 , not a single person was working. | ||||
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