How is due process related to the idea of equal protection?

First lets explain what due process and equal protection are. Equal protection or equal protection clause is the clause is part of the Fourteenth Amendment to the United States Constitution. The clause, which took effect in 1868, provides that no state shall deny to any person within its jurisdiction "the equal protection of the laws". Due process is fair treatment through the normal judicial system, especially as a citizen's entitlement. To answer your question they are related because they both maintain equality and fairness in the justice system.