Answer:
The answer is six to one of the sides
Explanation:
Total area of the given polygon = Area of triangle 1 + Area of rectangle 2 + Area of triangle 3
Area of triangle 1 = Area of triangle 3 = 
 = 
 = 4x square feet
Area of rectangle 2 = Length × Width
 = 16 × 8
 = 128 square feet
Total area of the given polygon = 4x + 128 + 4x
176 = 8x + 128
8x = 176 - 128
x = 
x = 6 ft