ziI really need some help on this one because I don't know how to do it

The trigonometric ratio sin (θ) is used to find angles of right triangles and is given by:
[tex]\sin (\theta)=\frac{\text{Opposite side}}{\text{ Hypotenuse}}[/tex]Graphically,
So, in this case, you have:
[tex]\begin{gathered} \sin (K)=\frac{5}{10} \\ \text{Simplifying} \\ \sin (K)=\frac{5\cdot1}{5\cdot2} \\ \sin (K)=\frac{1}{2} \end{gathered}[/tex]Therefore, the correct answer is option A.