
Start with a line segment AB that we will divide up into 5 (in this case) equal parts. 

Step 1 
From point A, draw a line segment at an angle to the given line,
and about the same length. The exact length is not important. 

Step 2 
Set the compasses on A, and set its width to a bit less than one fifth of the length of the new line. 

Step 3 
Step the compasses along the line, marking off 5 arcs. Label the last one C. 

Step 4 
With the compasses' width set to CB, draw an arc from A just below it. 

Step 5 
With the compasses' width set to AC, draw an arc from B crossing the one drawn in step 4. This intersection is point D. 

Step 6 
Draw a line from D to B. 

Step 7 
Using the same compasses' width as used to step along AC, step the compasses from D along DB making 4 new arcs across the line 

Step 8 
Draw lines between the corresponding points along AC and DB. 

Step 9 
Done. The lines divide the given line segment AB in to 5 congruent parts. 
