量角器也称半圆仪,是度量角的重要工具,在日常生产生活中应用得十分广泛。量角器包括五部分:一是量角器的中心,在量角器的中间下方,有一个圆圆的点,这个点就是量角器的中心;二是量角器的内刻度,从量角器的右边到左边标有0、10、20、30……180十九个数,这十九个数叫作内刻度;三是量角器的外刻度,从量角器左边到右边标有0、10、20、30……180 Protractor also known as semicircle instrument, is an important tool for measuring angle, in daily production and life has been widely used. Protractor consists of five parts: First, the center of the protractor, the middle of the protractor, there is a round point, this point is the center of the protractor; second protractor within the scale from the right side of the protractor to the left labeled 0,10, 20,30 ... 180 nineteen, the nineteen number is called the inner scale; third is the outer scale of the protractor, from the protractor left to the right labeled 0,10,20,30 ... 180