Answer:
 (c) 69.12 in²
Explanation:
You want the area of a rectangle that is 14.4 inches long and has a width 1/3 of its length.
Area
The formula for the area of a rectangle is ...
 A = LW
 A = (14.4 in)(1/3×14.4 in) = 69.12 in²
The area of the rectangle is 69.12 in².