By finding orthogonal representation for a family of simple connected called $δ$-graphs it is possible to show that $δ$-graphs satisfy delta conjecture. An extension of the argument to graphs of the form $\overline{P_{Δ(G)+2}\sqcup G}$ where $P_{Δ(G)+2}$ is a path and $G$ is a simple connected graph it is possible to find an orthogonal representation of $\overline{P_{Δ(G)+2}\sqcup G}$ in $\mathbb{R}^{Δ(G)+1}$. As a consequence we prove delta conjecture.