认识量角器介绍3-1.ppt

认识量角器,人们将圆平均分成360份。,每1份所对的角作为度量角的单位，它的大小就是1度，记作1,1,5,30,120,10,20,30,40,60,70,80,90,100,110,120,130,140,150,160,170,10,20,30,40,50,60,70,80,90,100,110,120,130,140,150,160,170,0,50,0,180,180,中心点,0度刻度线,外圈刻度,内圈刻度,0,0,二、探究新知,量角器,