First find the lengths of each side of the triangle.
Side NM is 12, side ML is 5, and side LN is 13.
A secant in trigonometry is the hypotenuse divided by the adjacent, so...
sec x = hypotenuse/adjacent
The hypotenuse of this triangle is side LN which is 13, and the adjacent to angle L is side ML which is 5.
Therefore, sec L = LN/ML.
sec L = 13/5
Therefore, the secant of angle L is 13/5.
