The formula for determining the area of a rhombus is expressed as
Area = base * height
From the diagram,
Area = 20 square inches
height = 1/3 ft
Recall, 12 inches = 1 ft
Thus, 1/3 ft = 1/3 * 12 = 4 inches
base = x
Thus,
20 = 4 * x
x = 20/4
x = 5
The correct answer is the first option