A bicycle wheel has radius R. Let P be a point on the spoke of a wheel at a distance d from the center of the wheel. The wheel begins to roll to the right along the the x-axis. The curve traced out by P is given by the following parametric equations:
$x = 13 \theta - 7 \sin(\theta)$
$y = 13 - 7 \cos(\theta)$

What must we have for R and d?
R=
d =