I have been staring a my notes and this question for a while now, and i CAN'T get i. Please help me!

Jack decides to ride the Ferris wheel. He boards the ride at 1m and is the last person on the ride. The diameter of the wheel is 16m and it takes 8 sec for one complete revolution. Find the equation that represents Jack's height in relation to time. Then use the equation to determine Jack's height after 35sec.

I think i will be bale to answer the second part of the question on my own. But i honestly can't get the equation. I have no idea what i am doing wrong.