Pi Day 2024 Theme Images. Pi (greek letter “ π ”) is the symbol used in mathematics to represent a constant — the ratio of the circumference of a circle to its diameter — which is approximately 3.14159. Find & download free graphic resources for pi day clip art vectors, stock photos & psd files.

Less searching, more finding with getty images. If you couldn’t already tell by the number this mathematical symbol represents, pi day is on thursday, march 14, 2024.