【简答题】如下图,请回忆老师引导你推导梯形面积公式的过程. (1)完全一样的梯形转化成平行四边形,其方法是______. A.旋转 B.平移 C.旋转和平移 (2)观察转化前的梯形与转化后的平行四边形,你发现了什么?(至少写三条.) (3)计算上面梯形的面积.(先动手在图中量出计算时需要的数据,再算出它的面积.)
【判断题】力F对任意点的矩,因F的作用点沿其作用线移动而改变
【简答题】(2011广西崇左,22,10分)(本小题满分10分)矩形、菱形、正方形都是平行四边形,但它们都是有特殊条件的平行四边形,正方形不仅是特殊的矩形,也是特殊的菱形.因此,我们可利用矩形、菱形的性质来研究正方形的有关问题.回答下列问题: (1)将平行四边形、矩形、菱形、正方形填入它们的包含关系的下图中. (2)要证明一个四边形是正方形,可先证明四边形是矩形,再证明这个矩形的_______相等;或者先证...
【单选题】A disk is rotating about its central axis like a merry-go-round (旋转木马) . The angular position θ (t) of a reference line on the disk is given by θ = -1.00 – 0.60 t + 0.25 t 2 . At what time t min does ...
【简答题】根据要求画图列式计算: (1)画一个底是4厘米高是2.5厘米的平行四边形,并计算出它的面积。 (2)画一个上底是1厘米,下底是3厘米,高是2厘米的直角梯形,并计算出它的面积。(3)画一个底和高都是2厘米的三角形,并计算它的面积。
【简答题】听对话,根据对话内容选择正确的答案。听三遍。 1. What time are they going to leave? A. Two o'clock. B. Three o'clock. 2. What does the woman like best? A. Playing basketball. B. Playing computer s. 3. What will the woma...
【简答题】听下面一段对话,回答第1-2题。 1. What time is it now? A. 9: 30. B. 9: 15. C. 8: 45. 2. Why does Tony want to go to school? A. He loves studying very much. B. He can play with many friends. C. He wants to have a go...