Answer
$0.5x^2-0.4x+0.3$
Work Step by Step
Step 1. Let the length be $y$ units; we have the area as $(x+0.2)y=0.5x^3-0.3x^2+0.22x+0.06$, which gives $y=\frac{0.5x^3-0.3x^2+0.22x+0.06}{x+0.2}$
Step 2. Using synthetic division as shown in the figure, we have $y=0.5x^2-0.4x+0.3$
