Question

how to draw 180 degree angle

Answer 1

180° angle is a angle of a straight line
you didn't need any protector , use your scale to draw a straight line and then make a point randomly on that line . then point your compass on make a semicircle . that's your 180 angle.

Answer 2

180° = straight line 
Draw a straight line and make a semicircle of any radius on tht line.