Recall that a semicircle is formed by a central angle with measure 180 degrees, therefore, the given angle represents:
[tex]\frac{285}{180}=\frac{19}{12}[/tex]
of a semicircle.
Now, recall that the central angle of one semicircle measures:
[tex]\pi\text{radians.}[/tex]
Therefore:
[tex]285^{\circ}=\frac{19}{12}\pi\text{ radians.}[/tex]
Answer:
[tex]\begin{gathered} \text{Fraction: 285}^{\circ}=\frac{19}{12}\text{ of a semicircle.} \\ \text{Angle measure: 285}^{\circ}=\frac{19}{12}\pi\text{ radians.} \end{gathered}[/tex]
