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 ...

Two quantities are said to be in direct proportion if they increase or decrease in the same ratio. If two amounts are directly proportional we can scale the quantities up by multiplying. 150 ml × 5 = ...

The problem, 229.--Plant and envelope curves: plant average cost, 230; average cost, 231; the envelope, 234.--Divisibility and economics of scale: reasons for successively lower minima, 235; the ...

With the Sundance Film Festival right around the corner, I thought it would be appropriate to re-publish a little post I wrote some time ago in the waning days of the 2008 fest. Originally published ...