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:
Square root of naturals.svg en Square roots of natural numbers as squares and of as the disk in the centre Integer ones are black irrational ones are cyan The red circle shows that equals to the diagonal of square Such number comparison wouldn be possible on equilateral triangles for example but would be possible on regular hexagons