22. 6. 2021 The backrest should be perpendicular to the seat base, not to the floor. Original 1920px Additional info Original 1920px Original 1920px File type: JPGFile size: 11 MBDimensions: 5000 × 3337 pxPublished: 22. 6. 2021 Related article: Are you sitting comfortably? What about safely?