A conical cup has a height of 21 cm and the diameter of its base is 18 cm. Then the amount of water it can hold is

Given, height $\left(h\right)=21\text{cm}$

Diameter of base $\left(d\right)=18\text{cm}$

Radius $\left(r\right)=9\text{cm}$

Volume of cone $\text{=}\frac{1}{3}\pi r^{2}h$

$=\frac{1}{3}\times \frac{22}{7}\times 9\times 9\times 21$

Amount of water it can hold $=1782{\text{cm}}^3$