01
Calculate the margins on each side
The patch is two centimetres wider than the marked area, so centring leaves one centimetre beyond each side. It is also two centimetres taller, leaving one centimetre above and below. These margins follow from the stated dimensions and alignment. They are not a recommended seam allowance for every material or technique. If the patch is shifted from the centre, the opposing margins change even though its size stays the same. Record the placement reference so a later sketch or measurement can be compared with the intended layout.
02
Keep area difference separate from attachment quality
The marked rectangle has area twelve square centimetres, while the patch has area thirty-two square centimetres. Their difference is twenty square centimetres. Under this centred flat layout, that is the patch area outside the marked rectangle. It does not measure bond strength, stitch security or expected service life. A larger area alone cannot establish a successful repair. The calculation helps describe the composition and coverage, while choices about material and attachment remain separate questions that the supplied numbers do not answer.
03
Save the proposal and record what is actually done
The reusable card contains item identifier, marked-area dimensions, patch dimensions, orientation, placement, side margins and proposed materials. Leave attachment method and completion status open until decided and performed. If an actual patch is later applied, record the method used and observations from the finished item rather than copying the proposal as proof of completion. Note any change in dimensions or position. This keeps the layout worksheet useful as a plan and the later record useful as evidence of what happened to that particular object.