Question

who found graph????
how was it found???

Answer 1

William Playfair (22 Sept 1759-11 Feb 1823) was the founder of the graph

Answer 2

The paper written by Leonhard Euler on the Seven Bridges of Königsberg and published in 1736 is regarded as the first paper in the history of graph theory.[7] This paper, as well as the one written by Vandermonde on the knight problem, carried on with the analysis situs initiated by Leibniz. Euler's formula relating the number of edges, vertices, and faces of a convex polyhedron was studied and generalized by Cauchy[8] and L'Huillier,[9] and represents the beginning of the branch of mathematics known as topology.