Respuesta :

Answer:

The height = 8 miles.

Step-by-step explanation:

Area of a trapezoid = h(a + b)/2   where h=the height and a and b are the 2 bases.

So we have:

21.2 = h(4 + 1.3)/2

5.3 h / 2 = 21.2

5.3h =  42.4

h = 42.4 / 5.3

h = 8.