中学生网络课堂本课配套习题挑战模式1/5
单选题
难度系数：
1.
如图，在平行四边形ABCD中，CE是∠DCB的平分线，F是AB的中点，AB=6，BC=4，则AE：EF：FB为（ ）
| A: 1：2：3 |
| B: 2：1：3 |
| C: 3：2：1 |
| D: 3：1：2 |
一次做对，真牛！
+5奖励规则>
- 提示1：PHA+5qC55o2u6aKY5oSP5Y+v55+l77yM4oigRENFPeKIoEJFQz3iiKBCQ0XvvIzmiYDku6VCRT1CQz0077ybPC9wPg==
- 提示2：PHA+QUU9QUItQkU9Ni00PTLvvIxFRj1BRi1BRT0zLTI9Me+8mzwvcD4=
- 提示3：PHA+5omA5LulRkI9QUY9M++8jOaJgOS7pUFF77yaRUbvvJpGQj0y77yaMe+8mjMuPC9wPg==
- 答案：Qg==
PGRpdj7op6PvvJriiLXlm5vovrnlvaJBQkNE5piv5bmz6KGM5Zub6L655b2i77yMPGJyPuKItOKIoERDRT3iiKBCRUM8YnI+4oi1Q0XmmK/iiKBEQ0LnmoTlubPliIbnur88YnI+4oi04oigRENFPeKIoEJDRTxicj7iiLTiiKBDRUI94oigQkNFPGJyPuKItEJDPUJFPTQ8YnI+4oi1RuaYr0FC55qE5Lit54K577yMQUI9Njxicj7iiLRGQj0zPGJyPuKItEVGPUJFLUZCPTE8YnI+4oi0QUU9QUItRUYtRkI9Mjxicj7iiLRBRe+8mkVG77yaRkI9Mu+8mjHvvJozPGJyPuaVhemAiUIuPC9kaXY+
本课配套习题挑战模式2/5
单选题
难度系数：
2.
如图，在平行四边形ABCD中，对角线AC与BD交于点O，∠OBC=90°，AC=8，BD=4，则△BCO的面积是（）
| A:
|
| B:
|
| C:
|
| D:
|
一次做对，真牛！
+5奖励规则>
- 提示1：PHA+55Sx5Zyo5bmz6KGM5Zub6L655b2iQUJDROS4re+8jOWvueinkue6v0FD5LiOQkTkuqTkuo7ngrlP77yM4oigT0JDPTkwwrDvvIxBQz0477yMQkQ9NO+8jOWPr+axguW+l09C5LiOT0PnmoTplb/vvJs8L3A+
- 提示2：PHA+55Sx5Yu+6IKh5a6a55CG77yM5Y+v5rGC5b6XQkPnmoTplb/vvJs8L3A+
- 提示3：PHA+PGltZyBzcmM9Imh0dHBzOi8vcDEucWluZ2d1by5jb20vRzEvTTAwLzAwLzU3L3JCQUNGRk1NVW4yRHhKc3ZBQUFDb2xjOEhOYzQzNC5wbmciIGRhdGEtY2tlLXNhdmVkLXNyYz0iaHR0cHM6Ly9wMS5xaW5nZ3VvLmNvbS9HMS9NMDAvMDAvNTcvckJBQ0ZGTU1VbjJEeEpzdkFBQUNvbGM4SE5jNDM0LnBuZyIgaGVpZ2h0PSI0MiIgd2lkdGg9IjEyMiI+PGJyPjwvcD4=
- 答案：Qg==
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
本课配套习题挑战模式3/5
单选题
难度系数：
3.
如图，在平行四边形ABCD中，AB=3cm，BC=5cm，对角线AC，BD相交于点O，则OA的取值范围是（ ）
| A: 2cm＜OA＜5cm |
| B: 2cm＜OA＜8cm |
| C: 1cm＜OA＜4cm |
| D: 3cm＜OA＜8cm |
一次做对，真牛！
+5奖励规则>
- 提示1：PHA+5qC55o2u5bmz6KGM5Zub6L655b2i5a+56KeS57q/5LqS55u45bmz5YiGT0E9T0M9PGltZyBzcmM9Imh0dHBzOi8vcDIucWluZ2d1by5jb20vRzEvTTAwLzIzLzQ1L3JCQUNFMU1NVW9EQ0xSSlpBQUFCSkY1YTdRYzM4Ni5wbmciIGRhdGEtY2tlLXNhdmVkLXNyYz0iaHR0cHM6Ly9wMi5xaW5nZ3VvLmNvbS9HMS9NMDAvMjMvNDUvckJBQ0UxTU1Vb0RDTFJKWkFBQUJKRjVhN1FjMzg2LnBuZyIgaGVpZ2h0PSI0MiIgd2lkdGg9IjciPkFDPC9wPg==
- 提示2：PHA+5qC55o2u5LiJ6KeS5b2i5LiJ6L655YWz57O7MmNt77ycQUPvvJw4Y208L3A+
- 答案：Qw==
PGRpdj7op6PvvJriiLXlubPooYzlm5vovrnlvaJBQkNE5Lit77yMQUI9M2Nt77yMQkM9NWNt77yMPGJyPuKItE9BPU9DPTxpbWcgc3JjPSJodHRwczovL3AyLnFpbmdndW8uY29tL0cxL00wMC8yMy80NS9yQkFDRTFNTVVvRENMUkpaQUFBQkpGNWE3UWMzODYucG5nIiBkYXRhLWNrZS1zYXZlZC1zcmM9Imh0dHBzOi8vcDIucWluZ2d1by5jb20vRzEvTTAwLzIzLzQ1L3JCQUNFMU1NVW9EQ0xSSlpBQUFCSkY1YTdRYzM4Ni5wbmciIGhlaWdodD0iNDIiIHdpZHRoPSI3Ij5BQywgMmNt77ycQUPvvJw4Y23vvIw8YnI+4oi0MWNt77ycT0HvvJw0Y20uPGJyPuaVhemAiUMuPC9kaXY+
本课配套习题挑战模式4/5
单选题
难度系数：
4.
如图，在Rt△ABC中，∠B=90°，AB=3，BC=4，点D在BC上，以AC为对角线的所有平行四边形ADCE中，DE最小的值是（ ）
| A: 2 |
| B: 3 |
| C: 4 |
| D: 5 |
一次做对，真牛！
+5奖励规则>
- 提示1：PHA+55Sx5bmz6KGM5Zub6L655b2i55qE5a+56KeS57q/5LqS55u45bmz5YiGT0Q9T0XvvIxPQT1PQz0yLjU8L3A+
- 提示2：PHA+5Z6C57q/5q615pyA55+t55+l77yM5b2TT0TiiqVCQ+aXtu+8jERF57q/5q615Y+W5pyA5bCP5YC8PC9wPg==
- 答案：Qg==
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
本课配套习题挑战模式5/5
单选题
难度系数：
5.
在面积为15的平行四边形ABCD中，过点A作AE垂直于直线BC于点E，作AF垂直于直线CD于点F，若AB=5，BC=6，则CE+CF的值为（ ）
| A:
|
| B:
|
| C:
|
| D:
|
一次做对，真牛！
+5奖励规则>
- 提示1：PHA+5qC55o2u5bmz6KGM5Zub6L655b2i6Z2i56ev5YWs5byP5rGC5Ye6QUXlkoxBRjxicj48L3A+
- 提示2：PHA+5pyJ5Lik56eN5oOF5Ya177yM5rGC5Ye6QkXjgIFERueahOWAvDwvcD4=
- 提示3：PHA+5Yip55So5Yu+6IKh5a6a55CG77yM5rGC5Ye6Q0XlkoxDRueahOWAvO+8jOebuOWKoOWNs+WPr+W+l+WHuuetlOahiDxicj48L3A+
- 答案：RA==
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
