We are given a rectangular rod made of brass that has a cross$-$section of $0\mathrm{.}35$ in $x0\mathrm{.}14$ in and a gage length, $1,$ of $2\mathrm{.}5in.$ A tensile load is applied to the member. Calculate the engineering strain that occurred during testing if the rod length is $2\mathrm{.}80$ in during testing, i$.$e$.$ the instantaneous length, $l_{i.}.$