This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Fotothek df tg Geometrie Planimetrie Proportion Kreis Figur. Scan Deutsche Fotothek dftg color MIKCenter Berlin GmbH Abbildung Nr und Frankfurt Main proportionale Streckenteilung Nr und proportionale Vergrerung oder Verkleinerung ebener Flchen innerhalb eines Kreises Papier Kupferstich cm Geometrie Planimetrie Proportion