Answer :
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]
[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]
