$V_{\text{cylinder}} = 450 \, \text{cm}^3$
$V_{\text{cone}} = \frac{1}{3} V_{\text{cylinder}} = \frac{1}{3} \times 450 = 150 \, \text{cm}^3$
$V_{\text{empty space}} = V_{\text{cylinder}} - V_{\text{cone}}$
$= 450 - 150 = 300 \, \text{cm}^3$
$\text{Answer: } 300 \, \text{cm}^3$