1. The problem asks for the volume of oil in a cylindrical tank that is half-full. 2. Volume of a full cylinder is given by the formula $$V = \pi r^2 h$$, where $r$ is the base radius and $h$ is the height. 3. Here, the radius $r = 120$ cm and full height $h = 150$ cm. 4. Since the tank is half-full, the height of the oil is half the cylinder's height: $$h_{oil} = \frac{150}{2} = 75$$ cm. 5. Calculate the volume of oil in cubic centimeters: $$V_{oil} = \pi (120)^2 (75) = \pi \times 14400 \times 75 = 1,080,000 \pi$$ cm$^3$. 6. Use $\pi \approx 3.1416$ to approximate: $$V_{oil} \approx 1,080,000 \times 3.1416 = 3,393,292.8$$ cm$^3$. 7. Convert cubic centimeters to litres knowing $1$ litre $= 1000$ cm$^3$: $$V_{oil, litres} = \frac{3,393,292.8}{1000} = 3393.3$$ litres. 8. Round to nearest litre: $$3393$$ litres. **Final answer: There are approximately 3393 litres of oil in the tank.