某学生测量了一个长方形花坛的周长和一条边的长度,发现周长是18米,其中一条边长是5米,那么与这条边相邻的另一条边的长度是____米。
💡 提示:点击下方 "查看答案" 查看解析,或 "提交答案" 后自动显示结果
首先将每天的温差相加:(+3) + (-2) + 0 + (+5) + (-1) = 3 - 2 + 0 + 5 - 1 = 5。然后将总温差除以天数5,得到平均温差:5 ÷ 5 = 1。因此,这5天的平均气温比标准气温高1℃。本题考查有理数的加减运算及平均数计算,属于有理数与数据整理的综合应用。
🏆
练习完成!
恭喜您完成了本次练习,继续加油提升!
💡 学习建议:您在一元一次方程的应用方面掌握良好,但仍有提升空间。建议重点复习方程求解步骤和实际应用问题。
[{"id":2527,"content":"某学生在操场上观察旗杆的投影。已知旗杆高6米,太阳光线与地面形成的仰角为30°,则此时旗杆在地面的投影长度为多少米?","type":"选择题","subject":"数学","grade":"九年级","stage":"初中","difficulty":"简单","answer":"A","explanation":"本题考查锐角三角函数的应用。旗杆、投影和太阳光线构成一个直角三角形,其中旗杆为对边,投影为邻边,太阳光线与地面的夹角为30°。根据正切函数定义:tan(30°) = 对边 \/ 邻边 = 6 \/ x。因为 tan(30°) = √3 \/ 3,所以有 √3 \/ 3 = 6 \/ x,解得 x = 6 \/ (√3 \/ 3) = 6 × 3 \/ √3 = 18 \/ √3。将分母有理化:18 \/ √3 = (18√3) \/ 3 = 6√3。因此,旗杆的投影长度为6√3米,正确答案为A。","options":[{"id":"A","content":"6√3"},{"id":"B","content":"3√3"},{"id":"C","content":"12"},{"id":"D","content":"2√3"}]},{"id":189,"content":"小明去文具店买笔记本,每本笔记本的价格是5元。他买了3本,付给收银员20元,应找回多少钱?","type":"选择题","subject":"数学","grade":"初一","stage":"初中","difficulty":"简单","answer":"A","explanation":"首先计算小明购买3本笔记本的总花费:每本5元,3本就是 5 × 3 = 15 元。他付了20元,所以应找回的钱是 20 - 15 = 5 元。因此正确答案是A。","options":[{"id":"A","content":"5元"},{"id":"B","content":"10元"},{"id":"C","content":"15元"},{"id":"D","content":"20元"}]},{"id":328,"content":"某学生在整理班级同学的身高数据时,制作了如下频数分布表。已知身高在150~160cm的学生人数占总人数的40%,总人数为50人,则身高在150~160cm的学生有多少人?","type":"选择题","subject":"数学","grade":"初一","stage":"初中","difficulty":"简单","answer":"B","explanation":"题目中已知总人数为50人,身高在150~160cm的学生占总人数的40%。要求这部分学生的人数,只需计算50的40%是多少。计算过程为:50 × 40% = 50 × 0.4 = 20。因此,身高在150~160cm的学生有20人。该题考查的是数据的收集、整理与描述中关于百分比和频数的实际应用,属于简单难度,符合七年级数学课程要求。","options":[{"id":"A","content":"15"},{"id":"B","content":"20"},{"id":"C","content":"25"},{"id":"D","content":"30"}]},{"id":209,"content":"某学生计算一个多边形的内角和时,使用了公式 (n - 2) × 180°,其中 n 表示边数。若该多边形有 5 条边,则其内角和为 _ 度。","type":"填空题","subject":"数学","grade":"初一","stage":"初中","difficulty":"简单","answer":"540","explanation":"根据多边形内角和公式 (n - 2) × 180°,将边数 n = 5 代入计算:(5 - 2) × 180° = 3 × 180° = 540°。因此,五边形的内角和为 540 度。","options":[]},{"id":282,"content":"某班级进行了一次数学测验,老师将成绩分为五个等级:优秀、良好、中等、及格、不及格。统计后发现,优秀人数占总人数的20%,良好占30%,中等占25%,及格占15%,不及格占10%。如果用扇形统计图表示这些数据,那么表示“良好”等级的扇形的圆心角是多少度?","type":"选择题","subject":"数学","grade":"初一","stage":"初中","difficulty":"简单","answer":"B","explanation":"扇形统计图中,每个部分所占的百分比对应圆心角占整个圆(360°)的比例。‘良好’等级占总人数的30%,因此其对应的圆心角为:360° × 30% = 360° × 0.3 = 108°。所以正确答案是B。","options":[{"id":"A","content":"90°"},{"id":"B","content":"108°"},{"id":"C","content":"120°"},{"id":"D","content":"135°"}]},{"id":2318,"content":"某校八年级学生进行体质健康测试,随机抽取了10名学生的1分钟跳绳成绩(单位:次)如下:120, 135, 140, 145, 150, 150, 155, 160, 165, 170。这组数据的中位数和众数分别是多少?","type":"选择题","subject":"数学","grade":"八年级","stage":"初中","difficulty":"简单","answer":"A","explanation":"首先将数据从小到大排列(已排好):120, 135, 140, 145, 150, 150, 155, 160, 165, 170。共有10个数据,为偶数个,因此中位数是第5个和第6个数据的平均数,即(150 + 150) ÷ 2 = 150。众数是出现次数最多的数,150出现了两次,其余数均只出现一次,因此众数为150。故正确答案为A。","options":[{"id":"A","content":"中位数150,众数150"},{"id":"B","content":"中位数147.5,众数150"},{"id":"C","content":"中位数150,众数145"},{"id":"D","content":"中位数147.5,众数145"}]},{"id":2188,"content":"某学生在数轴上标记了两个有理数点A和B,点A表示的数是-3\/4,点B位于点A右侧且与点A的距离为1.25个单位长度。若点B表示的数为x,则下列叙述中正确的是:","type":"选择题","subject":"数学","grade":"七年级","stage":"初中","difficulty":"中等","answer":"B","explanation":"点A表示-3\/4,即-0.75,点B在其右侧1.25个单位,因此x = -0.75 + 1.25 = 0.5。0.5是0和1这两个连续整数的平均数,因此选项B正确。选项A错误,因为x=0.5虽大于0,但题目问的是'一定',而若点B在左侧则可能为负,但本题中B在右侧已确定x=0.5;选项C错误,因为|x|=0.5<1虽成立,但选项表述为'小于1'看似正确,但结合选项B更准确且具数学意义;选项D错误,因为x + (-3\/4) = 0.5 - 0.75 = -0.25,为负数,但此结论依赖于计算,而B揭示了x的结构特征,更符合'正确叙述'的深层要求。综合分析,B为最佳答案。","options":[{"id":"A","content":"x一定大于0"},{"id":"B","content":"x可以表示为两个连续整数的平均数"},{"id":"C","content":"x的绝对值小于1"},{"id":"D","content":"x与-3\/4的和为负数"}]},{"id":2285,"content":"某学生在数轴上标记了三个点A、B、C,其中点A表示的数是-4,点B位于点A右侧6个单位长度处,点C位于点B左侧2个单位长度处。那么点C表示的数是___。","type":"填空题","subject":"数学","grade":"七年级","stage":"初中","difficulty":"简单","answer":"-0","explanation":"首先确定点B的位置:点A是-4,向右移动6个单位,即-4 + 6 = 2,所以点B表示的数是2。接着,点C在点B左侧2个单位,即2 - 2 = 0,因此点C表示的数是0。本题考查数轴上点的位置与有理数加减的实际应用,符合七年级学生对数轴的认知水平。","options":[]},{"id":2217,"content":"某学生在记录一周内每天的温度变化时,发现某天的气温比前一天上升了5℃,记作+5℃;第二天又下降了3℃,应记作____℃。","type":"填空题","subject":"数学","grade":"七年级","stage":"初中","difficulty":"简单","answer":"-3","explanation":"根据正负数表示相反意义的量的知识点,气温上升用正数表示,下降则用负数表示。下降了3℃,应记作-3℃,符合七年级学生对正负数在实际生活中应用的学习要求。","options":[]},{"id":1820,"content":"某班级在一次数学测验中,五名学生的成绩分别为:82分、76分、90分、88分和84分。这组成绩的平均数是多少?","type":"选择题","subject":"数学","grade":"八年级","stage":"初中","difficulty":"简单","answer":"B","explanation":"平均数的计算公式是:所有数据之和除以数据的个数。首先将五名学生的成绩相加:82 + 76 + 90 + 88 + 84 = 420。然后将总和除以人数5:420 ÷ 5 = 84。因此,这组成绩的平均数是84分,正确答案是B。","options":[{"id":"A","content":"82分"},{"id":"B","content":"84分"},{"id":"C","content":"86分"},{"id":"D","content":"88分"}]}]