The motion of an object vibrating at the end of a horizontal spring is described by the equation x=(0.25 cm)..?

The motion of an object vibrating at the end of a horizontal spring is described by the equation x=(0.25 cm)cos(pi*t/8). What is the period of the motion? I got the answer for this and I got 16 seconds. But then I am asked to find the position when t=1 second... the thing is, for the answer on my review it says .23m. I was wondering how to get this answer? PLEASE HEELLPPP