A trapezoid has an area of 21.2 square miles. One base is 4 miles long. The other base is 1.3 miles long. What is the height?

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.