The area of this trapezoid is 90 square feet. 
Explanation : 
Before we know the answer, let's we know the formula first. The formula for count the area of trapezoid is : 

If : 
- A = area of trapezoid 
- a = bottom bases of trapezoid 
- b = top bases of trapezoid 
- h = height of trapezoid 
Okay, let's we count its : 
We know that : 
- a = bottom bases of trapezoid = 18 feet 
- b = top bases of trapezoid = 12 feet
- h = height of trapezoid = 6 feet 
Question : A = area = ... ? 
Answer : 

Subject : Mathematics
Keyword : Count The Area of a shape