
根据直径是圆中最长的弦,知该圆的直径是10cm;最短弦即是过点P且垂直于过点P的直径的弦;根据垂径定理即可求得CP的长,再进一步根据勾股定理,可以求得OP的长.



下列命题中,假命题是( )
某校七年级1班50名同学在“森林草原防灭火”知识竞赛中的成绩如表所示:
成绩  | 60  | 70  | 80  | 90  | 100  | 
人数  | 3  | 9  | 13  | 16  | 9  | 
则这个班学生成绩的众数、中位数分别是( )
My aunt wanted to take a taxi so that she ________ get to the airport on time.

He ______ sleep,although he tried to. One cup of coffee in the late afternoon caused him tostay awake almost all night.
—What a lovely present!Who sent it? __________it be your brother?
—It __________be my brother. He doesn't know today is my birthday.
—Excuse me, are the glasses Mike’s?
—No, they __________be Mike’s. He doesn’t wear glasses.