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. Circlet, 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.

314

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

uponB.

Polygons From 8 To 12 Sides

Set the gauge-point upon c to 1 or 10 upon D; and against the length of one side upon D is the area upon C.

Sides 8 6 6 7 8 9 10 11 12.

Gauge-points .433 1.7 2.6 3.63 4.82 6.18 7.69 9.37 1117.

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.