How to create a pair of perpendicular lines from scratch.
Step 1: Draw a Line
Any size is fine.
Refer to this new line "Line 1".
Step 2: Create a Point
Create a point somewhere to the left or right of the line.
Refer to this point as "Point 1".
Step 3: Make an Arc
Place a compass on Point 1 and create an arc that intersects Line 1 at two different points.
Refer to this new arc as "Arc 1".
Step 4: Create a X
This is a multi-step process.
1.) Place one end of the compass on one of Arc 1's intersection points on Line one.
2.) Place the other end of the compass on the outside of Arc 1.
3.) Create an arc that crosses from one side of Point 1 to the other. (Refer to this new arc as "Arc 2".)
4.) Repeat process 1-3 with the starting point of the compass on the other intersection of Arc 1 and Line 1. (Refer to this new arc as "Arc 3".)
Make sure that both Arc 2 and Arc 3 intercept each other and make a somewhat x shape.
Step 5: Create the Perpendicular Line
Create a line through Point 1 and the intersection of Arc 2 and Arc 3.