As you probably know, squaring a number is pretty easy, we just multiply the number by itself and we have it.

For example, if we wanted the square of 9 we would do the calculation

9 x 9 = 81

Well the slide rule can do that too, but without any mental effort on your part!  It's a matter of moving the cursor and there it is!

However, finding square roots is more difficult isn't it.  For example, if we wanted to find the square root of 36, we would need to find a number when multiplied by itself would give 36.  This one is easy ...

6 x 6 = 36

So √36 = 6, but what about something like √14? This is too easy for the slide rule, another simple sliding of the cursor and we have it!  We need to remember that we can't give an exact answer to numbers like √14, √17 and √54; the best we can do is an approximation. So let's check out how to do this.