A Ferris wheel is 21 meters in diameter and boarded from a platform that is 1 meter above the ground. The six o'clock position on the Ferris wheel is level with the loading platform. The wheel completes 1 full revolution in 18 minutes. The function h(t) gives a person's height in meters above the ground t minutes after the wheel begins to turn. Required:
a. Find the amplitude, midline, and period of h(t).
b. Find a formula for the height function (t).
c. How high off the ground is a person after 3 minutes?