8．如果三角形的两边分别为3和5，那么连接这个三角形三边中点

所得的三角形的周长可能是(　　 )

A．4　　　　　　 B．4.5　　　　 　C．5　　　　　　　　　　　　 D．5.5

7．如图，在中，=90°，=10，若以点为圆心，

长为半径的圆恰好经过的中点，则的长等于(　　 )

A．　　　　　　　　　 B．5 　　　　　C．　　　　　　　　　　　 D．6

6．如图，，=30°，则的度数为(　　 )

　　　 A．20°　 　　　　　　　 B．30°　　　　　　　　　 C．35°　　　 　　　　 D．40°

5．用配方法解方程时，原方程应变形为(　　 )

　 A．　 　　　　　　　　　　　　　　　　 B．

　 C．　　　　　　　　　　　　　　　　　 D．

4．已知一个多项式与的和等于，则这个多项式是(　　 )

A．　　　 B．　　 C．　　　 D．

3．学业考试体育测试结束后，某班体育委员将本班50名学生的测试成绩制成如下的统计表．这个班学生体育测试成绩的众数是(　 　)

A．30分　　 　　　B．28分　　　　　　 C．25分　　　　　　 D．10人

2．下列计算中，结果正确的是(　　 )

　　　 A．　　 B．　　 C．　 D．

在每小题给出的四个选项中，只有一项符合题目要求，请选出并在答题卡上将该项涂黑.

1．在数轴上表示的点离开原点的距离等于(　　 )

A．2　 　　　　　　　　　 B．　 　　　　　　 C．　 　　　　　　 D．

26．(1)解：由得点坐标为

由得点坐标为

∴··················································································· (2分)

由解得∴点的坐标为···································· (3分)

∴··························································· (4分)

　 (2)解：∵点在上且

　　　　　　 ∴点坐标为······················································································ (5分)

又∵点在上且

∴点坐标为 全················································································· (6分)

∴··········································································· (7分)

　 (3)解法一：当时，如图1，矩形与重叠部分为五边形(时，为四边形)．过作于，则

∴即∴

∴

即··································································· (10分)

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25．解：(1)····································································································· (1分)

证明：(证法一)

由旋转可知，

∴···························································· (3分)

∴又

∴即··································· (4分)

(证法二)

由旋转可知，而

∴···························································· (3分)

∴∴

即·········································································· (4分)

　　　 (2)四边形是菱形. ················································································· (5分)

证明：同理

∴四边形是平行四边形. ························································· (7分)

又∴四边形是菱形. ··········································· (8分)

　　　 (3)(解法一)过点作于点，则

在中，

……(10分)

由(2)知四边形是菱形，

∴

∴························································ (12分)

(解法二)∴

在中，

　······················································ (10分)

∴································································ (12分)

(其它解法可参照给分)全品中　 考网