Answer
$x\approx4.39$
Work Step by Step
Use the definition of the natural log function to solve for $x$. Rewrite the problem so that the base has the exponent of the opposite side and is equal to the log's number and/or variable.
$\ln\sqrt {x+3}=1$
$e^1=\sqrt {x+3}$
$x+3=e^2$
$x=e^2-3$
$x\approx4.39$