This file is from Wikimedia Commons and may be used by other projects.
The description on its file description page there is shown below.
Summary
DescriptionA cone being held by a woman with volume formula.jpg
English: To find the volume of a cone, take the area of the base circle (which is pi times the radius squared), multiply it by the vertical height (a line from the apex or tip of the cone to the center of the base, which is at right angles to the base's diameter), and divide it by three.
The person who associated a work with this deed has dedicated the work to the public domain by waiving all of their rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.
http://creativecommons.org/publicdomain/zero/1.0/deed.enCC0Creative Commons Zero, Public Domain Dedicationfalsefalse