Chapter 6: Applications of Definite Integrals - Section 6.2 - Volumes Using Cylindrical Shels - Exercises 6.2 - Page 331: 43

$\dfrac{\pi r^2 h}{3}$

We need to use the Washer method as follows: $V=\int_p^{q} (2 \pi) \cdot (\space radius \space of \space shell) ( height \space of \space Shell) \space dy \\= \int_{0}^{r} (2\pi) \cdot (h-\dfrac{h x}{r}) dx \\=2 \pi \times \int_{0}^{r}[h x-\dfrac{hx^2}{r}] dx \\=\dfrac{\pi r^2 h}{3}$