Graphs and equations of proportion
Pages
The graph of direct proportion
A line through the origin, and why one that misses it is not direct proportion.
The graph of inverse proportion
The reciprocal curve, approaching each axis without ever reaching it.
Conversion graphs
Reading a conversion graph in both directions, and extending it with the rate.
Constructing y = kx
Finding k from one pair of values, then using the equation in both directions.
Constructing y = k/x
Writing inverse proportion as y = k/x, since it means proportional to 1/x.
Proportion to squares, cubes and roots
Relationships like y = kx² and y = k/x², and finding k when the power is stated.
Practice
Practice
Constructing y = kx
Finding k from one pair of values, then using the equation in both directions.
PracticeConstructing y = k/x
Writing inverse proportion as y = k/x, since it means proportional to 1/x.
PracticeEquations of proportion review
Constructing y = kx, y = k/x and power variants from one pair — Higher only.