Problem $2$: The density of atmospheric air varies with elevation $($from the surface of the world$),$ decreasing with increasing altitude. Using the data given in the table, obtain a relation $(2^{nd}$ order polynomial$)$ by using Excel for the variation of density with elevation, and calculate the density at an elevation of $7km.$

$\backslash$table$[[z(km),,k\frac{g}{m}3$