Determine the Equation of the Graph $13 \mathrm { ft }$

Determine the equation of the graph.
-A rotating beacon is located $13 \mathrm { ft }$ from a wall. The distance from the beacon to the point on the wall where the beacon is aimed is given by
$$a = 13 | \sec 2 \pi t | \text {, }$$
where $t$ is time measured in seconds since the beacon started rotating. Find a for $t = 0.41$ seconds. Ro your answer to the nearest hundredth.

A) $15.40 \mathrm { ft }$
B) $31.00 \mathrm { ft }$
C) $46.60 \mathrm { ft }$
D) $- 15.40 \mathrm { ft }$ nd