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1、名师精编优秀教案29.1投影(1)导学案【学习目标】1、经历实践探索,了解投影、投影面、平行投影和中心投影的概念;2、了角平行投影和中心投影的区别。3、学会关注生活中有关投影的数学问题,提高数学的应用意识。【学习重点】理解平行投影和中心投影的特征【学习难点】在投影面上画出平面图形的平行投影或中心投影【导学过程】一、合作学习,探究新知自学提纲:1、投影的定义:一般地,叫做物体的 投影,照射光线叫做投影线,投影所在的平面叫做投影面2、投影的分类(1)平行投影平行投影 的定义:是平行投影如物体在太阳光的照射下形成影子(简称日影)就是平行投影太阳光与影子的关系:物体在太阳光照射的不同时刻,不但影子的大
2、小在变化,而且影子的方向也在变化(2)中心投影中心投影 的定义:叫做中心投影 如物体在灯泡发出的光线照射下形成影子就是中心投影产生中心投影光源的确定:分别自两个物体的顶端及其影子的顶端作一条直线,这两条直线的交点即为光源的位置(3)如何判断平行投影与中心投影:分别自两个物体的顶端及其影子的顶端作一条直线,若两直线平行,则为平行投影;若两直线相交,则为中心投影,其交点是光源的位置二、教师点拨:例 1:王丽和赵亮两个小朋友晚上在广场的一盏灯下玩,如图1,AB的长表示王丽的身高,BM表示她的影子,CD的长表示赵亮的身高,DN表示他的影子,请画出这盏灯的位置.A C D B 图 1 N M 名师精编优
3、秀教案例 2、某时刻两根木棒在同一平面内的影子如图所示,此时,第三根木棒的影子表示正确的是【】例 3:如图,路灯距地面8 米,身高1.6 米的小明从距离灯的底部(点O)20 米的点 A处,沿 OA 所在的直线行走14 米到点 B 时,人影的长度【】A增大 1.5 米B.减小 1.5 米C.增大 3.5 米D.减小 3.5 米三、针对练习:1探照灯、手电筒、路灯等的光线可以看成是从_个点发出的,像这样的光线所形成的投影称为 _.2投影可分为_和_;一个立体图形,共有_种视图.3在太阳光的照射下,矩形窗框在地面上的影子常常是_形,在不同时刻,这些形状一般不一样.3下列物品探照灯;车灯;太阳;月亮;
4、台灯中所成的投影是中心投影的是()A.B.C.D.4太阳发出的光照在物体上是_,车灯发出的光照在物体上是_()A.中心投影,平行投影B.平行投影,中心投影C.平行投影,平行投影D.中心投影,中心投影5.图 1 是一天中四个不同时刻两个建筑物的影子:将它们按时间先后顺序进行排列,正确的是()A、B、C、D、文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1
5、R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9
6、B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T
7、5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8
8、S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3
9、X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ
10、1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6
11、F8S1R4R9 ZG10Y3X9B9C2名师精编优秀教案6如图,身高为16m 的某学生想测量一棵大树的高度,她沿着树影BA 由 B 到 A 走去,当走到 C 点时,她的影子顶端正好与树的影子顶端重合,测得BC=3.2m,CA=0.8m,则树的高度为()(A)4.8m(B)6.4m(C)8m(D)10m 7.在同一时刻的阳光下,小明的影子比小强的影子长,那么在同一路灯下()A、小明的影子比小强的影子长B、小明的影子比小强的影子短C、小明的影子和小强的影子一样长D、无法判断谁的影子长8.某数学课外实验小组想利用树影测量树高。他们在同一时刻测得一身高为1.5m 的同学影长为 1.35m,因为大树靠
12、近一幢建筑物,影子不会在地面上(如图 1),他们测得地面部分的影长 BC 3.6m,墙上影长CD 1.8m,则树高AB 为。9.张明同学想利用树影测量校园内的树高他在某一时刻测得小树高为1.5 米时,其影长为1.2 米当他测量教学楼旁的一棵大树影长时,因大树靠近教学楼,有一部分影子在墙上经测量,地面部分影长为6.4 米,墙上影长为1.4 米,那么这棵大树高约米10.如图 2,晚上,小亮在广场上乘凉图2 中线段 AB 表示站立在广场上的小亮,线段PO表示直立在广场上的灯杆,点P 表示照明灯(1)请你在图中画出小亮在照明灯(P)照射下的影子;(2)如果灯杆高PO12m,小亮的身高AB 1.6m,小
13、亮与灯杆的距离BO13m,请求出小亮影子的长度ABCDE图图 1 文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F
14、8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y
15、3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:C
16、Z1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI
17、6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG1
18、0Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码
19、:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2名师精编优秀教案11.一位同学身高1.6 米,晚上站在路灯下,他身体在地面上的影长是2 米,若他沿着影长的方向移动 2 米站立时,影长增加了0.5 米,求路灯的高度.12(6 分)如图,现有m、n
20、两堵墙,两个同学分别站在A 处和 B 处,请问小明在哪个区域内活动才不被则两个同学发现(画图用阴影表示)。13(6 分)路灯下站着小赵、小芳、小刚三人,小芳和小刚的影长如图,确定图中路灯灯泡的位置,并画出小赵在灯光下的影子P A B O 图 2 小亮文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D
21、9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1
22、R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9
23、B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T
24、5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8
25、S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2文档编码:CZ1T5D9R7J6 HI6F8S1R4R9 ZG10Y3X9B9C2
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