Answer
$300\pi\approx942.48\ in^2$
Work Step by Step
Given $r_1=30, r_2=30-24=6, \theta=125^\circ=\frac{25\pi}{36}$, the area swept by the blade is the difference of the total swept by $r_1$ and the uncovered area from $r_2$, thus $A=\frac{1}{2}(r_1^2-r_2^2)\theta=\frac{1}{2}(30^2-6^2)(\frac{25\pi}{36})=300\pi\approx942.48\ in^2$