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一、试题还原在初二一次平行四边形单元测试中,一道教师认为送分的题目得分率却低得惊人.题目:已知:如图1,在矩形ABCD中,对角线BD的垂直平分线MN与AD相交于点M,与BC相交于点N,连接BM,DN.(1)求证:四边形BMDN是菱形;(2)若AB=4,AD=8,求菱形BMDN的面积.据统计,第(1)题得分率仅为0.31;第(2)题得分率0.52!值得深思!二、现象透视在阅卷中,出现以下情形.情形一审题马虎张冠李戴镜头透视1谁是谁的中垂线!学生解答:∵MN是BD的中垂线,∴OM=ON.(下面再证△MOD与△NOB全等)点评:曲解题意,MN是BD的中垂线,理
First, the test questions in the first two parallel quadrilateral unit test, a teacher that points to send the subject scoring rate is surprisingly low. Title: Known: As shown in Figure 1, in the rectangular ABCD, the vertical bisector of the diagonal BD Line MN and AD intersect at point M, and BC intersect at point N, connect BM and DN. (1) Verify that the quadrilateral BMDN is rhombus; (2) If AB = 4 and AD = 8, find the area of diamond BMDN Statistics, the first (1) score of only 0.31; (2) score of 0.52! Worth pondering! Second, the phenomenon of perspective in the marking, the following situations occur. Vertical line! Student Answer: ∵ MN is the vertical line of BD, ∴ OM = ON. (Below and then check △ MOD and △ NOB congruent) Comments: misunderstanding, MN is the BD vertical line,