square feet
Explanation:
Here we have , the top of a display counter at a store is in the shape of a trapezoid . the lengths of the front back and with in feet of the top of the display counter . Complete question is given below , We need to find area of trapezoid with dimensions :

Area of trapezoid =

⇒

⇒

⇒

⇒

⇒

Therefore,
square feet.