Sacred Geometry: A Primer

Today, how to find the golden section division of a line.You start off with a line, mine was 4 inches.

I guess I sort of skipped a step, you need to make a vertical line

like so, but you need to find the half way mark of your first line and then your vertical line needs to be the same as half of your first line. I picked a line length that was easily divisible so that I already knew the half. I think that was harder than it needed to be.
Draw a diagonal to make a triangle.

Set your compass with the point on the top point of the triangle, put the drawing point on the bottom left corner of the triangle and arc up to meet the diagonal line.

Then set your point on the left corner of the triangle and the drawing point on the intersection between the diagonal and the arc. Arc down, that is the golden section division of the line.