Choose the appropriate method to draw the following angles, and tell what kind of angles they are. (1) 140°______ angle (2) 45°______ angle (3) 180°

The analysis and drawing are as follows:

(1) 140° obtuse angle, drawn with a protractor;

(2) 45 °Acute angle, use an isosceles right triangle to draw it;

(3) 180° is a straight angle,;

So the answer is: obtuse, acute, straight angle.