Year 8 Maths — Introduction to graphs

Plot and read points on a grid, read a line graph, and work out values from a simple linear relation.

Name: ________________________

Before you start

This graph follows one journey from start to finish, with time along the bottom and distance up the side. Find out what each stretch of the line says about it.

1. Rising — moving away
2. Flat — standing still
3. Steeper — faster
4. The origin

Flat does not mean time has stopped — the clock still runs along the bottom. It means the distance stopped changing, and standing still is exactly what that looks like on a graph.

1.A line graph shows a plant 4 cm tall on day 1 and 16 cm tall on day 7. How much did it grow over those six days, in cm? Give just the number.
2.On a distance-time graph, what does a flat horizontal part of the line mean?
- a) The object is going backwards
- b) The graph has been drawn wrongly
- c) The object is speeding up
- d) The object is not moving
3.Sort each point by where it sits on the grid.
Groups: On the x-axis · On the y-axis · On neither axis
- (0, -1)
- (2, 7)
- (-4, 0)
- (0, 5)
- (6, 6)
- (3, 0)
4.A car travels at a steady 50 km per hour. On a distance-time graph, how far has it gone after 3 hours, in km? Give just the number.
5.A shop sells notebooks at $20 each. On a graph of cost against number bought, what is the cost of 7 notebooks? Give just the number.
6.This distance-time graph shows one journey in three parts. Tap the part where the car was not moving.
Write the number of the part.
7.A point sits 4 units to the right of the origin and 7 units up. Write its y-coordinate.
8.For the relation y = 3x, what is y when x is 6?

Answer key — Year 8 Maths — Introduction to graphs

1. 12
2. d) The object is not moving
3. (3, 0) → On the x-axis; (0, 5) → On the y-axis; (2, 7) → On neither axis; (-4, 0) → On the x-axis; (0, -1) → On the y-axis; (6, 6) → On neither axis
4. 150
5. 140
6. 2 — Stopped by the roadside
7. 7
8. 18