Answer:
29.58 mi²
Step-by-step explanation:
The figure is a trapezium and area can be calculated using the formula
A =
h(a + b)
where h is the height and a, b the parallel bases
here h = 3.4, a = 5.4 and b = 12
A = 0.5 × 3.4(5.4 + 12) = 1.7 × 17.4 = 29.58 mi²