1/5单选题
难度：
1.如图，将半径为2cm的圆形纸片折叠后，圆弧恰好经过圆心O，则折痕AB的长为（ ）
| A |  |
| B |  |
| C |  |
| D |  |
- 提示1：
- IOi/h+WchuW/g+S9nOWeguebtO+8jOWcqOWbvuS4reaehOW7uuebtOinkuS4ieinkuW9ou+8mw==
- 提示2：
- IOagueaNruWLvuiCoeWumueQhuW+l0FE55qE6ZW/77yM77yb
- 提示3：
- IOWGjeagueaNruWeguW+hOWumueQhuW+l0FC55qE6ZW/Lg==
正确答案：Qw==
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
2/5单选题
难度：
2.
如图，⊙O的半径是3，点P是弦AB延长线上的一点，连接OP，若OP=4，∠APO=30°，则弦AB的长为（）
| A |
|
| B |
|
| C |
|
| D |
|
- 提示1：
- PHA+5YWI6L+HT+S9nE9D4oqlQVDvvIzov57nu5NPQjs8L3A+
- 提示2：
- PHA+5qC55o2uT1A9NO+8jOKIoEFQTz0zMMKw77yM5rGC5Ye6T0PnmoTlgLw7PC9wPg==
- 提示3：
- PHA+5ZyoUnTilrNCQ0/kuK3vvIzmoLnmja7li77ogqHlrprnkIbmsYLlh7pCQ+eahOWAvO+8jOWNs+WPr+axguWHukFC55qE5YC8LjwvcD4=
正确答案：QQ==
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
3/5单选题
难度：
3.
如图，圆心在y轴的负半轴上，半径为5的⊙B与y轴的正半轴交于点A（0，1），过点P（0，-7）的直线l与⊙B相交于C，D两点. 则弦CD长的所有可能的整数值有（ ）
| A | 1个 |
| B | 2个 |
| C | 3个 |
| D | 4个 |
- 提示1：
- PHA+5YiG5oOF5Ya16K6o6K6677ybPC9wPg==
- 提示2：
- PHA+5b2TQ0TlnoLnm7TlnIbnmoTnm7TlvoRBReaXtu+8jOaxguWHuue6v+autUNE55qE5pyA5bCP5YC877ybPC9wPg==
- 提示3：
- PHA+5b2TQ0Tnu4/ov4flnIblv4Pml7bvvIxDROeahOWAvOacgOWkp++8jOaxguWHuuacgOWkp+WAvO+8jOWPluWcqOiMg+WbtOWGheWPluaVtOaVsOOAgjwvcD4=
正确答案：Qw==
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
4/5单选题
难度：
4.
如图圆O直径AB上一点P，AB=2，∠BAC=20°，D是弧BC中点，则PD+PC的最小值为（ ）
| A |
|
| B | 1 |
| C |
|
| D |
|
- 提示1：
- PHA+5L2cROeCueWFs+S6jkFC55qE5a+556ew54K5Re+8jOi/nkNF5LqkQULkuo5Q54K577yM6L+eRUPvvJs8L3A+
- 提示2：
- PHA+5rGC5Ye65bynREM95bynQkQ9MjDCsO+8jFBEPVBF77ybPC9wPg==
- 提示3：
- PHA+5qC55o2u5Lik54K55LmL6Ze057q/5q615pyA55+t5b6X5YiwQ0XmmK9QRCtQQ+eahOacgOWwj+WAvC48L3A+
正确答案：Qg==
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
5/5单选题
难度：
5.在半径为13的⊙O中，弦AB∥CD，弦AB和CD的距离为7，若AB=24，则CD的长为（ ）
| A | 10 |
| B |  |
| C | 10或 |
| D | 10或 |
- 提示1：
- IOagueaNrumimOaEj+eUu+WHuuWbvuW9ou+8jOeUseS6jkFC5ZKMQ0TnmoTkvY3nva7kuI3og73noa7lrprvvIzmlYXlupTliIZBQuS4jkNE5Zyo5ZyG5b+DT+eahOWQjOS+p+WSjEFC5LiOQ0TlnKjlnIblv4NP55qE5byC5L6n5Lik56eN5oOF5Ya16L+b6KGM6K6o6K66Ow==
- 提示2：
- IOagueaNruWeguW+hOWumueQhuaxguWHuuW8pumVv++8mw==
正确答案：RA==
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