滬教版四年級上冊數(shù)學-54-幾何小實踐(角的度量)課件

滬教版四年級上冊數(shù)學-54-幾何小實踐(角的度量)課件1212猜一猜，∠1和∠2誰大？12∠2﹥∠1猜一猜，∠1和∠2誰大？12∠2﹥∠121221212∠2比∠1大多少度？★∠2和∠1分別包含了多少個1°角12∠2比∠1大多少度？★∠2和∠1分別包含了多少個1°21∠2比∠1大多少度？10°10°10°10°10°10°10°∠2比∠1大10度！0°10°20°30°0°10°20°30°40°∠1=30°∠2=40°21∠2比∠1大多少度？10°10°10°10°10°101313310°10°10°10°10°10°10°10°10°10°10°10°10°10°10°10°∠3=160°0°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°310°10°10°10°10°10°10°10°10°10310°10°10°10°10°10°10°10°10°10°10°10°10°10°10°10°0°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°10°10°170°180°310°10°10°10°10°10°10°10°10°100°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°0°10°20°30°40°50°60°70°80°90°1120°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°∠1=30°我知道了！∠2是140°！10°10°10°10°0°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°10°0°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°∠2=40°30°120°10°20°30°40°50°60°70°80°900°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°10°0°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°210°10°20°30°40°50°60°70°80°90°1AOB∠AOB=60°0°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°10°0°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°AOB∠AOB=60°0°10°20°30°40°50°600°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°10°0°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°COD0°10°20°30°40°50°60°70°80°90°1COD∠COD=65°COD∠COD=65°量角器中心零刻度線零刻度線量角器中心零刻度線零刻度線合作學習1、完成練習一，組內(nèi)交流測量的方法和結(jié)果合作學習1、完成練習一，組內(nèi)交流測量的方法和結(jié)果AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB50你會量出下圖中∠AOB的度數(shù)嗎？AOB50判斷1∠1=20°∠1=15°判斷1∠1=20°∠1=15°判斷BOC∠BOC=145°判斷BOC∠BOC=145°判斷5∠5=135°∠5=125°判斷5∠5=135°∠5=125°這個角磨損了，聰明的你有辦法知道它原來的角度嗎？原來是50°這個角磨損了，聰明的你有辦法知道它原來的角度嗎？原來是50猜一猜，下面的角可能是多少度？猜一猜，下面的角可能是多少度？猜一猜，下面的角可能是多少度？猜一猜，下面的角可能是多少度？合作學習1、嘗試完成練習二，如果遇到困難，可請教學習同伴或老師？2、完成后在組內(nèi)交流，你測量的結(jié)果是多少？你是怎么測量的？你們的測量方法有哪些相同點和不同點？合作學習1、嘗試完成練習二，如果遇到困難，可請教學83°比一比，誰能估得又對又快？83°比一比，誰能估得又對又快？68°比一比，誰能估得又對又快？68°比一比，誰能估得又對又快？146°比一比，誰能估得又對又快？146°比一比，誰能估得又對又快？

放風箏比賽時，規(guī)定用30米長的線。比哪個風箏放得高？該怎么辦呢？

只要把每根風箏線的一端固定在地面上，分別量出它們與地面所形成的角的度數(shù)。你知道嗎？放風箏比賽時，規(guī)定用30米長的線。比哪個風箏放得高？該怎滬教版四年級上冊數(shù)學-54-幾何小實踐(角的度量)課件滬教版四年級上冊數(shù)學-54-幾何小實踐(角的度量)課件護珠斜塔護珠斜塔：上海市松江天馬山護珠塔，比比薩斜塔早建近百年。目前此塔向東偏離2.28米、傾斜度6.63度、超過傾斜度5.2度的比薩斜塔一度多，據(jù)說，當?shù)氐娘L向大都由東南吹來，風力正頂著傾斜的塔身，這就是此塔長傾不倒的主要原因。護珠斜塔護珠斜塔：上海市松江天馬山護珠塔，比比薩斜塔早建近百

比薩斜塔1990年停止向游人開放時，傾斜角度約5.3°

，2001年修復后重新開放時，傾斜角度約3.9°

。意大利政府稱，可繼續(xù)維持300年不倒。你知道嗎？比薩斜塔1990年停止向游人開放時，傾斜椅子的靠背總是往后傾。用于學習的椅子，一般后傾8度；吃飯的椅子，一般后傾9度；沙發(fā)靠背則后傾11度左右。

椅子的靠背總是往后傾。用于學習的椅子，一般后傾8度；吃飯的椅山地車的車架構(gòu)造特殊，車座和操作控制梁的角度在71—74度之間，這個角度讓人騎起來比較舒服。

山地車的車架構(gòu)造特殊，車座和操作控制梁的角度在71—74度之打羽毛球時，應注意45度角度。

打羽毛球時，應注意45度角度。我們游泳劃水時手掌角度在20到45度之間最好。我們游泳劃水時手掌角度在20到45度之間最好。

發(fā)射角度是42.4°，因為它著陸場就位于42.4度左右。這樣，飛船每次經(jīng)過42.4度時，就通過著陸場，使飛船每天至少有一次返回的機會。發(fā)射角度是42.4°，因為它著陸場就位于42.4度滬教版四年級上冊數(shù)學-54-幾何小實踐(角的度量)課件滬教版四年級上冊數(shù)學-54-幾何小實踐(角的度量)課件1212猜一猜，∠1和∠2誰大？12∠2﹥∠1猜一猜，∠1和∠2誰大？12∠2﹥∠121221212∠2比∠1大多少度？★∠2和∠1分別包含了多少個1°角12∠2比∠1大多少度？★∠2和∠1分別包含了多少個1°21∠2比∠1大多少度？10°10°10°10°10°10°10°∠2比∠1大10度！0°10°20°30°0°10°20°30°40°∠1=30°∠2=40°21∠2比∠1大多少度？10°10°10°10°10°101313310°10°10°10°10°10°10°10°10°10°10°10°10°10°10°10°∠3=160°0°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°310°10°10°10°10°10°10°10°10°10310°10°10°10°10°10°10°10°10°10°10°10°10°10°10°10°0°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°10°10°170°180°310°10°10°10°10°10°10°10°10°100°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°0°10°20°30°40°50°60°70°80°90°1120°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°∠1=30°我知道了！∠2是140°！10°10°10°10°0°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°10°0°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°∠2=40°30°120°10°20°30°40°50°60°70°80°900°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°10°0°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°210°10°20°30°40°50°60°70°80°90°1AOB∠AOB=60°0°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°10°0°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°AOB∠AOB=60°0°10°20°30°40°50°600°10°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°10°0°20°30°40°50°60°70°80°90°100°110°120°130°140°150°160°170°180°COD0°10°20°30°40°50°60°70°80°90°1COD∠COD=65°COD∠COD=65°量角器中心零刻度線零刻度線量角器中心零刻度線零刻度線合作學習1、完成練習一，組內(nèi)交流測量的方法和結(jié)果合作學習1、完成練習一，組內(nèi)交流測量的方法和結(jié)果AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB你會量出下圖中∠AOB的度數(shù)嗎？AOB50你會量出下圖中∠AOB的度數(shù)嗎？AOB50判斷1∠1=20°∠1=15°判斷1∠1=20°∠1=15°判斷BOC∠BOC=145°判斷BOC∠BOC=145°判斷5∠5=135°∠5=125°判斷5∠5=135°∠5=125°這個角磨損了，聰明的你有辦法知道它原來的角度嗎？原來是50°這個角磨損了，聰明的你有辦法知道它原來的角度嗎？原來是50猜一猜，下面的角可能是多少度？猜一猜，下面的角可能是多少度？猜一猜，下面的角可能是多少度？猜一猜，下面的角可能是多少度？合作學習1、嘗試完成練習二，如果遇到困難，可請教學習同伴或老師？2、完成后在組內(nèi)交流，你測量的結(jié)果是多少？你是怎么測量的？你們的測量方法有哪些相同點和不同點？合作學習1、嘗試完成練習二，如果遇到困難，可請教學83°比一比，誰能估得又對又快？83°比一比，誰能估得又對又快？68°比一比，誰能估得又對又快？68°比一比，誰能估得又對又快？146°比一比，誰能估得又對又快？146°比一比，誰能估得又對又快？

放風箏比賽時，規(guī)定用30米長的線。比哪個風箏放得高？該怎么辦呢？

只要把每根風箏線的一端固定在地面上，分別量出它們與地面所形成的角的度數(shù)。你知道嗎？放風箏比賽時，規(guī)定用30米長的線。比哪個風箏放得高？該怎滬教版四年級上冊數(shù)學-54-幾何小實踐(角的度量)課件滬教版四年級上冊數(shù)學-54-幾何小實踐(角的度量)課件護珠斜塔