Answer:
Step-by-step explanation:

The length of other base of trapezoid is 10 miles
Step-by-step explanation:
The formula for area of trapezoid is:

We know that
A = 42 square miles
b_1 = 4 miles
h = 6 miles
Putting the values

The length of other base of trapezoid is 10 miles
Keywords: Area of trapezoid
Learn more about area at:
#LearnwithBrainly
Just plot it and solve by counting