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.

2. Circles, Polygons, etc.

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 0.433 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.