Answer: 25 in.
Step-by-step explanation:
Given
Arc length is 34 inches
The angle subtended by the arc is [tex]78^{\circ}[/tex]
arc length l subtending an angle [tex]\theta[/tex] is given by
[tex]\Rightarrow l=\dfrac{\theta }{360^{\circ}}\times 2\pi R[/tex]
Put the values
[tex]\Rightarrow 34=\dfrac{78^{\circ}}{360^{\circ}}\times 2\pi R\\\\\Rightarrow R=24.97\approx 25\ in.[/tex]