Data Sufficiency on Quadrilateral Land Area

Let the quadrilateral be $ABCD$ with right angles at $\angle A = 90^\circ$ and $\angle C = 90^\circ$. Diagonal $BD$ is the hypotenuse for right-angled triangles $\Delta ABD$ and $\Delta CBD$. Perimeter $AB + AD + BC + CD = 700$. Statement I gives $AD = 110$ ft. (Not sufficient alone). Statement II gives diagonal length $BD = 255$ ft. (Not sufficient alone). Combining both: In $\Delta ABD$, $AB = \sqrt{BD^2 - AD^2} = \sqrt{255^2 - 110^2} \approx 230$. Then $BC + CD = 700 - (110 + 230) = 360$. Since $\Delta CBD$ is right-angled at $C$, $BC^2 + CD^2 = BD^2 = 255^2$. We can uniquely determine $BC$ and $CD$, and thus find the area of both triangles, giving the total area and total cost. Hence, I and II together are minimally sufficient.