True
Explanation
Step 1
[tex]\cos \theta=\frac{adjacent\text{ side}}{\text{hypotenuse}}[/tex]
then
[tex]\begin{gathered} \cos \theta=\frac{adjacent\text{ side}}{\text{hypotenuse}}=\frac{12}{13} \\ \\ \frac{adjacent\text{ side}}{\text{hypotenuse}}=\frac{12}{13} \\ \text{adjacent side=12} \\ \text{hypotenuse}=13 \end{gathered}[/tex]
Step 2
find y,use Pythagoras theorem
[tex]\begin{gathered} a^2+b^2=c^2 \\ 12^2+y^2=13^2 \\ y^2=13^2-12^2 \\ y^2=25 \\ \sqrt[]{y^2}=\sqrt[]{25} \\ y=5 \end{gathered}[/tex]Step 3
find sine of theta
[tex]\begin{gathered} \sin \text{ }\theta=\frac{opposite\text{ side}}{\text{hypotenuse}} \\ \text{replace} \\ \sin \text{ }\theta=\frac{y}{13} \\ \sin \text{ }\theta=\frac{5}{13} \end{gathered}[/tex]so, the answer is
TRUE
I hope this helps you