### If $A$ and $B$ are acute angles such that $cot{\space} A$ = $tan{\space} B$, find the value of $(A + B )$.

$90^\circ$
1. We are told that \begin{aligned} &cot{\space} A = tan{\space} B \\ {\implies}& cot{\space} A = cot{\space} (90^\circ - B) \\ {\implies}& A = 90^\circ - B &&[\because A{\space}{\space} and {\space}{\space}(90^\circ - B ){\space} are{\space} acute. ] \\ {\implies}& A + B = 90^\circ \end{aligned}
2. Thus, the value of $(A + B)$ is $\bf 90^\circ$.