Answer
a. $59.4 \ mi.$
b. $197\ mi^2 .$
Work Step by Step
a. The perimeter of the trapezoid is given by
$$perimeter = Sum\ of \ all\ sides\\
= 20 +12+14+13.42 =59.4 \ mi.$$
b. The area is given by $$Area=\frac{Sum\ of \ parallel\ bases}{2}\times height\\ \frac{20+14}{2} \times 11.6= 197\ mi^2 .$$
