The gradient or the steepness of the graph can be used to work out the speed ... The speed of the vehicle following the green line for the first 3 seconds is speed = distance ÷ time = gradient ...

This graph shows the cost of petrol. It shows that 20 litres will cost £23 or £15 will buy 13 litres. Gradient = \(\frac{\text{change up}}{\text{change right}}\) or \(\frac{\text{change in y}}{\ ...