Answer
$4\sqrt{2}\approx5.657 \text{ } ft
$
Work Step by Step
The ramp forms a right triangle. Let $c$ be the hypotenuse and $a,b$ be the legs of the right triangle. Using $a^2+b^2=c^2$ or the Pythagorean Theorem, where $c=6$ and $a=2,$ then
\begin{array}{l}\require{cancel}
a^2+b^2=c^2
\\\\
2^2+b^2=6^2
\\\\
4+b^2=36
\\\\
b^2=36-4
\\\\
b^2=32
\\\\
b=\sqrt{32}
\\\\
b=\sqrt{16\cdot2}
\\\\
b=\sqrt{(4)^2\cdot2}
\\\\
b=4\sqrt{2}
.\end{array}
Hence, the base of the ramp (which has the same value as $b$) is equal to $
4\sqrt{2}\approx5.657 \text{ } ft
.$