The pairs of numbers are called ordered pairs because the order they are written is very important. The first number always tells the distance to move along the horizontal axis from the point labeled 0. The second number tells the distance to move along the vertical axis from 0. The ordered pair (0,0) is called the origin.

In laboratory investigations, the first number of the ordered pair is the value of the variable on the horizontal axis. The second number is the value of the variable on the vertical axis. So, for Jerome's investigation, the ordered pairs are:

(Hand Length, Height)


  • Make sure you see how Jerome graphed his brothers' and sisters' data.
  • Use the graph to find the hand length and height of Jerome's parents.
  • What are the ordered pairs for the points for Jerome's parents?

Besides measuring their own family members, Irma and Jerome measured their classmates as well. They also collected data from other families, schoolchildren, and even teachers. When they finished graphing all the data, the graph represented Hand Length vs. Height for their neighborhood.