In an experiment, length = 2.54 cm, radius = 0.25 cm. The volume of the cylinder with proper significant figures is:

Volume $V=\pi r^2h=\pi(0.25)^2(2.54)\approx 0.4987\,\text{cm}^3$. The least precise measured quantity is $0.25$, which has 2 significant figures so the result must be reported to 2 significant figures: $0.50\,\text{cm}^3$.