Current Attempt in Progress

A platform is rotating with an angular speed of $3\mathrm{.}00ra\frac{d}{s}$ and an angular acceleration of $11\mathrm{.}0ra\frac{d}{s^2}.$ At a point on the platform that is $1\mathrm{.}20m$ from the axis of rotation, what is the magnitude of the total acceleration $a?$

$a=$