Answer
The length of the pendulum is $0.25~m$
Work Step by Step
We can find the length of the pendulum:
$T = 2\pi~\sqrt{\frac{L}{g}}$
$(\frac{T}{2\pi})^2 = \frac{L}{g}$
$L = \frac{T^2~g}{(2\pi)^2}$
$L = \frac{(1.0~s)^2~(9.80~m/s^2)}{(2\pi)^2}$
$L = 0.25~m$
The length of the pendulum is $0.25~m$.
