To calculate speed, use the formula:

$\text{Speed} = \frac{\text{Distance}}{\text{Time}}$

Substituting the given values:

$\text{Speed} = \frac{1125 \text{ m}}{250 \text{ s}} = 4.5 \text{ m/s}$

So, the speed is 4.5 m/s.

Would you like further details or have any questions? Here are some related questions you might find interesting:

1. What is the formula for calculating speed in different units, such as km/h?
2. How does changing the distance affect the speed if the time remains constant?
3. How can you calculate time if you know the speed and distance?
4. What are the common units used for speed, and how do you convert between them?
5. How does average speed differ from instantaneous speed?

Tip: When working with speed, always ensure that the units of distance and time are compatible (e.g., meters and seconds) before performing calculations.