x =a) 110b) 145c) 220

If the inner arc is x, then the outer arc is 360 - x

[tex]70 = \frac{1}{2} ((360 - x) - x)[/tex]

[tex]70 = \frac{1}{2} (360 - 2x)[/tex]

[tex]70 = 180 - x[/tex]

[tex]x = 180 - 70[/tex]

[tex]x = 110 \textdegree[/tex]