# Distance-time graphs

A graph with time across and distance up. The gradient of the line is the speed.

Maths (school) · Part 04: Graphs · Card 8 of 8 · Last updated 2026-10-19

## Analogy

Like a diary of a journey: steep means fast, flat means you have stopped.

## Example

**60 km in 1.5 hours**

Speed = distance / time
= 60 / 1.5
= 40 km/h

## In practice

Delivery apps track a rider with a distance-time graph to estimate arrival.

## Practice

### Flashcards

- **What is the speed if a car goes 60 km in 1.5 hours?** 40 km/h. Speed is distance divided by time.

## Questions people ask

### What does a flat line mean on a distance-time graph?

A flat horizontal line means the distance is not changing, so the object is stationary. Time keeps passing but the distance stays the same. A steeper line means a faster speed. A line sloping back down means the object is returning.

### How do you find speed from a distance-time graph?

Find the gradient of the line. Divide the distance covered by the time taken for that section. A line rising 60 km over 1.5 hours has a speed of 60 / 1.5 = 40 km/h. Check the units on each axis.

## Related concepts

- [Coordinates](https://studyvisually.com/learn/science/maths-school/maths-school-part-4/maths-school-part-4-concept-1)
- [Gradient](https://studyvisually.com/learn/science/maths-school/maths-school-part-4/maths-school-part-4-concept-2)
- [y = mx + c](https://studyvisually.com/learn/science/maths-school/maths-school-part-4/maths-school-part-4-concept-3)
- [Parallel and perpendicular lines](https://studyvisually.com/learn/science/maths-school/maths-school-part-4/maths-school-part-4-concept-4)

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