Step 1:Using a ruler or a straight edge, draw line segment AB Step 2: Using your compass tool, draw a circle with the center being point A that has a radius that is larger than half the length of line AB ( don't change your compass) Step 3: Now use that same compass measure, and make another circle with the center being point B Step 4: Where the two circles intersect, name those two points C and D Step 5: Using a ruler or line segment tool, draw a line from point C to point D Step 6: Where line AB and line CD meet, name that point E That line intersection at point E is a perfect 90 degree angle