Try: 3.6 X 2.9 using the CI scale

  1. Similar procedure as the first example above, but note that using the C & D scales requires moving the slide a very long distance.
  2. You might prefer to use your CF and DF scales, which have 99 and 11 very near the center of the rule. This minimizes slide movement. Your answer can be read on D at the right index of C ... or on DF at the index of CF.
  3. Using the CI scale method would also minimize slide movement for this problem.
  4. Dividing 1 by 11, then multiplying by 99 is yet another method that works well for this problem.
  5. Using the A and B scales can also solve this problem. Note that both 99 and 11 appear on the second section, or “decade”, of these scales.