When Slide Rules Ruled

Make your own slide rule

+

=

2 x 3

…………….

20 x 3

2 x 6

355/113

355/113 to 5 decimal places

Standard 10 inch Rule

355/113 = 3.14

20 inch Rule

355/113 = 3.14

Otis King66 inch Helical Rule

355/113 = 3.142

Fuller 41 foot Helical Rule

355/113 = 3.1416

The Cursor can be a simple indicator, or a memory

1.5 x 3 x 42

The CI (inverted C) scale is the reciprocal of the C scale, and

assists with chain multiplications and divisions.

1.5 x 3 x 42

You accidentally drop your i-phone from a height of 3.5 feet while

playing angry birds. How quickly must you react and catch it before it

is toast?

443.5DistanceTime

You are at an outdoor concert, standing 20 feet from an omnidirectional speaker where the loudness is 105 decibels. Your parents

say you must limit your exposure to 95 decibels. You double your distance from the

speaker. Is that far enough?2

2

1log10

DDdB

2

4020log1010

?

What is the sine of 0.02 radians?

What is Ln 1.006?

What is e-0.09?

Ln(1+x) = x – x2/2 + x3/3 - …

ex = 1 + x + x2/2! + x3/3! …

~ 0.02(0.019999)

~ 0.91(0.914)

Ln(1+x) = x – x2/2 + x3/3 - … ~ 0.006(0.00598)

ex = 1 + x + x2/2! + x3/3! …