Mensuration Of Surface
Description
This section is from the book "The Tinman's Manual And Builder's And Mechanic's Handbook", by Isaac Ridler Butt. Also available from Amazon: The Tinman's Manual And Builder's And Mechanic's Handbook.
Mensuration Of Surface
1. Squares, Rectangles, etc.
Rule. - When The Length Is Given In Feet And The Breadth In Inches, Set The Breadth On B To 12 On A; And Against The Length On A Is The Content In Square Feet On B
If the dimensions are all inches, set the breadth on b to 144 upon A; and against the length upon a is the number of square feet on B.
Required the content of a board 15 inches broad and 14 feet long. Set 15 upon b to 12 upon a; and against 14 upon a is 17.5 square feet on B.
Rule. - Set .7854 upon c to 1 or 10 upon D; then will the lines c and D be a table of areas and diameters.
Areas | 3,14 | 7.06 | 12.56 | 19.63 | 28.27 | 38.48 | 50.26 | 63.61 | upon C: |
Diam. | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | upon D. |
In the common rule, set .7854 on c to 10 on d; then c is a line or table of areas, and D of diameters, as before.
Set 7 upon b to 22 upon a; then b and a form or become a table of diameters and circumferences of circles.
Cir. | 3.14 | 6 28 | 9.42 | 12.56 | 15.7 | 18.85 | 22 | 25.13 | 28.27 | upon a. |
Dia. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | upon b. |
Polygons from 3 to 12 sides.-Set the gauge-point upon c to 1 or 10 upon D; and against the length of one side upon v is the area upon C.
Sides | 3 | 5 | c | 7 | 8 | 9 | 10 | 11 | 12 |
Gauge-points | .433 | 1.7 | 2.6 | 3.63 | 4.82 | 6.18 | 7.69 | 9.37 | 11.17 |
Required the area of an equilateral triangle, each side 12 inches in length.
Set. 433 upon c to 1 upon D; and against 12 upon D are 62.5 square inches upon c.
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