Answer
csc $A$ = $\frac{15}{9}$
Work Step by Step
If the secant ratio is the inverse of the cosine ratio, then we just reverse the sides in the cosine ratio to get the secant ratio.
If sec $A$ = $\frac{adjacent}{hypotenuse}$, then:
sec $A$ = $\frac{hypotenuse}{adjacent}$.
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Let's look at angle $A$. The hypotenuse has a length of $15$, and the side adjacent to $A$ has a length of $9$.
csc $A$ = $\frac{15}{9}$