GCSE Maths - What Does Directly Proportional Mean? #89

The video explains direct proportionality, using hours worked and amount earned as an example. It describes how directly proportional variables increase or decrease at the same rate, and how this relationship is represented on a graph as a straight line passing through the origin. The video also demonstrates how to use such graphs to calculate earnings for different hours worked. Finally, it summarizes the concept, emphasizing that directly proportional variables maintain a consistent ratio.

What does it mean for two variables to be directly proportional?

• One variable increases while the other decreases.

• Both variables decrease at different rates.

• Both variables increase or decrease at the same rate.

• One variable remains constant while the other changes.

If you work 5 hours and earn 60 pounds, how much would you earn for 10 hours?

• 120 pounds

• 100 pounds

• 80 pounds

• 60 pounds

What is a key feature of a graph showing a direct proportional relationship?

• It is a horizontal line.

• It has multiple peaks.

• It passes through the origin.

• It is a curved line.

How much would you earn if you worked 3.5 hours, according to the graph?

• 35 pounds

• 30 pounds

• 42 pounds

• 50 pounds

What happens to one variable if the other is halved in a direct proportional relationship?

• It doubles.

• It remains the same.

• It is halved.

• It triples.