# The time taken by a pendulum to complete 20 vibrations is $88.0$ second. The time period of the pendulum is

$\begin{array}{1 1} 4\;s \\ 4.4\;s \\ 4.40 \;s \\4.400\;s \end{array}$

Answer :$4.40 \;s$
Only three significant figures are required in the result.