利用定积分的几何意义，求定积分$\int_{0}^{3} \sqrt{9 - 考试宝

单选题利用定积分的几何意义，求定积分$\int_{0}^{3} \sqrt{9 - x^2} dx = ($ ）

A、 $\frac{\pi}{2}$

B、 $\frac{3\pi}{4}$

C、 $\frac{4\pi}{3}$

D、 $\frac{9\pi}{4}$

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