#### Answer

\[b=\frac{2A}{h}\].

#### Work Step by Step

The provided formula is\[A=\frac{1}{2}bh\] and now solve the formula for \[b\] by multiplying both the sides by \[\frac{2}{h}\]
\[\begin{align}
& A=\frac{1}{2}bh \\
& \frac{2}{h}\times A=\frac{{}}{{}}\times \frac{1}{{}}b \\
& b=\frac{2A}{h}
\end{align}\]
The formula \[A=\frac{1}{2}bh\]is for area of a triangle, where \[A=\] area of the triangle, \[b=\] base of the triangle, and\[h=\] height of the triangle.
The formula is\[b=\frac{2A}{h}\].