We can use the formula for the period of a pendulum:
T = 2π√(L/g)
where T is the period, L is the length of the pendulum, and g is the acceleration due to gravity (9.8 m/s^2).
Rearranging the formula to solve for L, we get:
L = (gT^2)/(4π^2)
Plugging in the given values, we get:
L = (9.8 m/s^2) x (3.17 s)^2 / (4π^2) = 2.00 m
Therefore, the length of the pendulum is approximately 2.00 m.