since we know that 180° is really π radians, then, what is 85°?
[tex]\bf \begin{array}{ccll}
de grees&radians\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
180&\pi \\
85&x
\end{array}\implies \cfrac{180}{85}=\cfrac{\pi }{x}\implies x=\cfrac{85\pi }{180}\implies x=\cfrac{17\pi }{36}[/tex]
