How do we know if a graph represents either direct or inverse proportionality? We look for certain features of the graph and perform some test calculations to help us decide. Look at this graph: The ...

The value \(e\) is directly proportional to \(p\). When \(e = 20\), \(p = 10\). Find an equation relating \(e\) and \(p\). \(e \propto p\) \(e = kp\) \(20 = 10k\) so ...