# QGIS Single sided buffer value of specific area and line length on 90 degrees lines

I need to Single Sided Buffer a specific surface based on a line length, on QGIS.

Example:

• line length: 60.367 meters.
• area needed from single sided buffer: 452.4 square meters.
• theoretic Single sided buffer value: 452.4/60.367 = 7.49 meters.

Issue: On corner where the line turns at any angle, I lose some of that surface. For example at a 90 degrees with the values mentioned theoretically I lose 7.49 * 7.49 = 56.10 square meters.

I have tried to modify the formula by: area_needed/line_length + buffer_value^2.

But even that addition loses some surface trough lines buffer intersection, thus it would have been needed an iteration until surface matches perfectly.

In the example below, the intersected surface is lost:

Question: How do I solve the buffer value calculus from dividing surface needed by line length, to something consistent that adds up the missing surface.

As mentioned below: By "summing up the missing area in all these intersections - adding this to the area needed and recalculate" it increases the buffer value but it still does not reach the desired area.

It seems I lose some surface with buffer parts that are outside the polygon within I measure that area. Also, buffer being perpendicular with the generating line and not with the polygon where area is measured within.