Question

How to draw a 120 degree angle with compass?

Answer 1

1). Use Ruler and draw a Line segment BC of any convenient length.



2). Now use compass and open it to any convenient radius. And with B as center , draw an arc which cuts line segment BC at Q .


3). Again use compass and opened to the same radius (as of step 2). And with Q as center , draw an arc which cuts first arc at R .



4). Again use compass and opened to the same radius (as of step 2). And with R as center , draw another arc which cuts first arc at P .



5). Join BP and extent it to A .



6) Above formed angle ABC = 120 Degree