Answer
$\frac{1075\pi}{3}\approx1125.74\ in^2$
Work Step by Step
Given $r_1=34, r_2=34-25=9, \theta=120^\circ=\frac{2\pi}{3}$, the area swept by the blade is the difference of the total swept by $r_1$ and the uncovered area from $r_2$, thus $A=\frac{1}{2}(r_1^2-r_2^2)\theta=\frac{1}{2}(34^2-9^2)(\frac{2\pi}{3})=\frac{1075\pi}{3}\approx1125.74\ in^2$