Slide rule, second version

This slide rule has two copies of the basic ruler, joined end-to-end.

There is also an equally-spaced number line, for measuring actual distances on the slide rule.

There is also a measuring stick, for testing whether two distances are equal. To change the length of the measuring stick, drag O. To move the measuring stick without changing its length, drag N.

There is also a differently spaced ruler, A, labeled in the same way real slide rules were. Ruler A has two cycles of the basic ruler (C or D), but shrunk to fit in half the space.

Try this:

Use the measuring stick or the number line to figure out how the spacing works. Initially, the measuring stick is set to the distance from 1 to 2. Measure off this same distance from 2 to the right. What number is there? Repeat until you run off the end.

Try it again with the length of the measuring stick the distance from 1 to 3.

Figure out how to use ruler A to find square roots.

Susan Addington, Created with GeoGebra