90 [lect. iv*
LIST OF PLATES
belonging to
LECTURE IV.
PRINCIPLES OF PROPORTION,
PLATE I.
RULE the line A. B. then, by the estimation of the'
eye, only divide it into four parts, by placing truly
the points 1. 2. 3. if any error appear in the copy thus
divided,—to prove it, open the compasses to the
distance A. 1, and measure the intervals.
2. Rule C. D. divide it, in the same manner, into
three parts, by placing the point 1.2. correctly;
as before.
3. Draw, by the eye E. F. the exact length of the
interval 1. D.
4. Divide, by the eye, a line equal to G. H.
into two parts and half, by the points 1. 2.
5. Draw, by the eye I. K. the exact interval of
1. B.
6. Draw a line equal to L. M. divide it by the eye
exactly in half; as 1.
7. Draw a line equal to N. O. divide it by the eye
into six equal parts; by the points 1. 2. 3. 4. 5.
1
PRIN-
LIST OF PLATES
belonging to
LECTURE IV.
PRINCIPLES OF PROPORTION,
PLATE I.
RULE the line A. B. then, by the estimation of the'
eye, only divide it into four parts, by placing truly
the points 1. 2. 3. if any error appear in the copy thus
divided,—to prove it, open the compasses to the
distance A. 1, and measure the intervals.
2. Rule C. D. divide it, in the same manner, into
three parts, by placing the point 1.2. correctly;
as before.
3. Draw, by the eye E. F. the exact length of the
interval 1. D.
4. Divide, by the eye, a line equal to G. H.
into two parts and half, by the points 1. 2.
5. Draw, by the eye I. K. the exact interval of
1. B.
6. Draw a line equal to L. M. divide it by the eye
exactly in half; as 1.
7. Draw a line equal to N. O. divide it by the eye
into six equal parts; by the points 1. 2. 3. 4. 5.
1
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