Go to your drawing table. Draw a horizontal line and a vertical line. Where they intersect place your compass point and draw a 10 inch(or 10 cm) arc intersecting both lines. now measure a point from the center out 0.8715 inches (or cm) [this is equal to 10cos(85)] and place a mark on the horizontal line. draw a vertical line from this point to the arc. Draw a dark line from where this vertical intersects the arc to the center. Darken the horizontal line. these two darkened lines form an 85 degree angle.
remember the formula: [radius] x cos(angle)
note: the larger the arc the more accurate the angle .
you first measure it on your protractor correctly then you use it:)
With a protractor and a straight edge.
use trisection method
There are 60 minutes in 1 degree.
Draw a point, and a long straight line through it. Put the centre of the compass over the point, with north on the compass (or zero degrees) on the line. Then draw a second line out from the point at 80 degrees on the compass. You'll then have a 80 degree angle between the lines. It's usually a trick that teachers decide to do on their pupils. A compass is what you use to find north and a pair of compasses is used to draw circles.
By bisecting an angle of 164 degrees or use the compass with the help of a protractor.
pad khaoo !!
Use a ruler
In conjunction with a straight edge and a protractor.
you first measure it on your protractor correctly then you use it:)
With a protractor and a straight edge.
By bisecting a 15 degree angle with a straight edge and a compass.
use trisection method
bisect between 120 and 180 degree ( 120 + 180= 300/2 =150)
It is possible to construct a 20 degree angle using only Ruler and Compass. I happened to stumble across a method that is highly accurate. It is posted on my blog. Check the related link
by using a ruler and a compass
by 60 degree and 90 degree