The law of sines states that:
[tex]\frac{\sin\alpha}{a}=\frac{\sin\beta}{b}=\frac{\sin \gamma}{c}[/tex]
where alpha is the opposite angle to side a, beta is the opposite angle to side b and gamma is the opposite angle to side c.
For the triangle given we notice that:
Angle x is opposite to side 2.5.
Angle 28° is opposite to side 3.
Therefore the expression to find x is:
[tex]\frac{\sin x}{2.5}=\frac{\sin 28}{3}[/tex]
