某学生调查了班级同学最喜欢的课外活动,并将结果整理成如下条形统计图(图中数据已给出):阅读12人,运动18人,绘画10人,音乐15人。请问喜欢运动的人数比喜欢绘画的人数多百分之几?
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因为 a = 6 且 a 与 b 关于原点对称,所以 b = -6。a 与 b 之间的距离为 |6 - (-6)| = 12。c 是该距离的一半,即 12 ÷ 2 = 6 个单位长度。但题目中 c 是位于 a 与 b 之间距离的一半位置,即从 a 向左移动 6 个单位或从 b 向右移动 6 个单位,最终都到达原点 0。因此 c = 0。
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[{"id":2249,"content":"在数轴上,点A表示的数是-3,点B与点A之间的距离为5个单位长度,且点B在原点右侧。那么点B表示的数是多少?","type":"选择题","subject":"数学","grade":"七年级","stage":"初中","difficulty":"简单","answer":"B","explanation":"点A在数轴上表示-3,点B与点A的距离为5个单位长度。由于点B在原点右侧,说明点B表示的数大于0。从-3向右移动5个单位,即-3 + 5 = 2,因此点B表示的数是2。选项B正确。","options":[{"id":"A","content":"-8"},{"id":"B","content":"2"},{"id":"C","content":"8"},{"id":"D","content":"5"}]},{"id":2512,"content":"某学生用三根长度分别为5 cm、12 cm、13 cm的木棒拼成一个三角形,并将其绕长度为5 cm的边旋转一周,形成一个立体图形。若该三角形中长度为5 cm的边所对的角为θ,则sinθ的值为多少?","type":"选择题","subject":"数学","grade":"九年级","stage":"初中","difficulty":"简单","answer":"B","explanation":"首先判断三角形类型:5² + 12² = 25 + 144 = 169 = 13²,满足勾股定理,因此这是一个直角三角形,且直角位于5 cm和12 cm两边之间。所以,长度为13 cm的边是斜边。题目中要求的是长度为5 cm的边所对的角θ的正弦值。在直角三角形中,正弦值等于对边比斜边。角θ的对边是12 cm,斜边是13 cm,因此sinθ = 12\/13。选项B正确。虽然题目提到了旋转,但实际考查的是锐角三角函数的基本概念,旋转信息为干扰项,不影响核心计算。","options":[{"id":"A","content":"5\/13"},{"id":"B","content":"12\/13"},{"id":"C","content":"5\/12"},{"id":"D","content":"12\/5"}]},{"id":2477,"content":"如图,在平面直角坐标系中,点 A(0, 4),点 B(6, 0),点 C 在 x 轴正半轴上,且 △ABC 是等腰三角形,AB = AC。过点 A 作直线 l 垂直于 BC,垂足为点 D。点 E 是线段 AD 上一点(不与 A、D 重合),连接 BE 并延长交 y 轴于点 F。已知直线 BE 的解析式为 y = kx + b,且满足 k = -\\\\frac{1}{2}。若四边形 AOFC 的面积为 15,其中 O 为坐标原点,求点 C 的横坐标。","type":"解答题","subject":"数学","grade":"八年级","stage":"初中","difficulty":"中等","answer":"待完善","explanation":"解析待完善","options":[]},{"id":159,"content":"下列各数中,属于正整数的是( )","type":"选择题","subject":"数学","grade":"初一","stage":"初中","difficulty":"简单","answer":"D","explanation":"正整数是指大于0的整数。选项A是负整数,选项B是0(既不是正数也不是负数),选项C是小数,只有选项D的7是大于0的整数,因此选D。","options":[{"id":"A","content":"-3"},{"id":"B","content":"0"},{"id":"C","content":"1.5"},{"id":"D","content":"7"}]},{"id":2135,"content":"某学生在解一元一次方程时,将方程 3(x - 2) = 2x + 1 的括号展开后得到 3x - 6 = 2x + 1,接着移项合并同类项,最终得到的解是 x = a。请问 a 的值是多少?","type":"选择题","subject":"数学","grade":"七年级","stage":"初中","difficulty":"简单","answer":"B","explanation":"首先展开方程左边:3(x - 2) = 3x - 6,原方程变为 3x - 6 = 2x + 1。将含 x 的项移到左边,常数项移到右边:3x - 2x = 1 + 6,得到 x = 7。因此正确答案是 B。","options":[{"id":"A","content":"5"},{"id":"B","content":"7"},{"id":"C","content":"8"},{"id":"D","content":"9"}]},{"id":1772,"content":"某学生在平面直角坐标系中画出一个三角形ABC,其中点A的坐标为(2, 3),点B在x轴上,点C在y轴上,且三角形ABC的面积为6。若点B的横坐标为正,点C的纵坐标为正,则点B的坐标为____,点C的坐标为____。","type":"填空题","subject":"数学","grade":"七年级","stage":"初中","difficulty":"困难","answer":"(4, 0), (0, 3)","explanation":"设B(b, 0),C(0, c),利用三角形面积公式S = 1\/2 × |b| × |c| = 6,结合A(2,3)共面关系,解得b=4,c=3,故B(4,0),C(0,3)。","options":[]},{"id":638,"content":"某班级在一次数学测验中,收集了30名学生的成绩,并将成绩分为5个分数段进行统计。已知前四个分数段的人数分别为4、7、9、6,则第五个分数段的人数是多少?","type":"选择题","subject":"数学","grade":"初一","stage":"初中","difficulty":"简单","answer":"B","explanation":"题目考查的是数据的收集与整理。总人数为30人,前四个分数段的人数分别为4、7、9、6。将这些人数相加:4 + 7 + 9 + 6 = 26。因此,第五个分数段的人数为30 - 26 = 4。所以正确答案是B。","options":[{"id":"A","content":"3"},{"id":"B","content":"4"},{"id":"C","content":"5"},{"id":"D","content":"6"}]},{"id":2,"content":"下列方程中,是一元一次方程的是?","type":"选择题","subject":"数学","grade":"初一","stage":"初中","difficulty":"简单","answer":"B","explanation":"一元一次方程指只含有一个未知数,且未知数的次数是1的整式方程。","options":[{"id":"A","content":"x² + 2x = 0"},{"id":"B","content":"3x - 5 = 0"},{"id":"C","content":"x + y = 5"},{"id":"D","content":"1\/x + 2 = 0"}]},{"id":1089,"content":"某学生调查了班级40名同学每天用于体育锻炼的时间(单位:分钟),并将数据整理如下:30分钟的有8人,40分钟的有12人,50分钟的有15人,60分钟的有5人。则这组数据的众数是____分钟。","type":"填空题","subject":"数学","grade":"七年级","stage":"初中","difficulty":"简单","answer":"50","explanation":"众数是指一组数据中出现次数最多的数值。根据题目中的数据:30分钟对应8人,40分钟对应12人,50分钟对应15人,60分钟对应5人。其中50分钟的人数最多,为15人,因此这组数据的众数是50分钟。","options":[]},{"id":1981,"content":"某学生在纸上画了一个边长为10 cm的正方形,并在正方形内部以一条对角线为轴,将正方形绕该对角线旋转180°。旋转后,原正方形的一个顶点所经过的路径长度为多少?(π取3.14)","type":"选择题","subject":"数学","grade":"九年级","stage":"初中","difficulty":"简单","answer":"A","explanation":"本题考查旋转与圆的综合应用。正方形边长为10 cm,其对角线长度为√(10² + 10²) = √200 = 10√2 cm。当正方形绕其中一条对角线旋转180°时,不在这条对角线上的两个顶点将绕该对角线作圆周运动。每个顶点到旋转轴(对角线)的距离等于正方形中心到顶点的垂直距离。由于正方形中心到任一顶点的距离为对角线的一半,即5√2 cm,而该距离在垂直于旋转轴的平面上的投影即为旋转半径。实际上,该顶点绕轴旋转的轨迹是一个半圆,其半径等于正方形边长的一半乘以√2,即 (10\/2) × √2 × sin(45°) = 5√2 × (√2\/2) = 5 cm。因此,旋转180°所经过的路径为半个圆周:π × 5 = 3.14 × 5 = 15.7 cm。","options":[{"id":"A","content":"15.7 cm"},{"id":"B","content":"31.4 cm"},{"id":"C","content":"22.2 cm"},{"id":"D","content":"10.0 cm"}]}]