Using the Pythagorean theorem the formula would look:
[tex]c^2=b^2+a^2\Longrightarrow3.4^2=3^2+a^2[/tex]
Now just solve for a.
[tex]a^2=3.4^2-3.0^2\Longrightarrow a=\sqrt{3.4^2-3.0^2} \\
a=\sqrt{11.56-9}=\sqrt{2.56}=\boxed{1.6}
[/tex]
Side a is 1.6 inches long.
Hope this helps.
r3t40
