6128An ESSAY
ſinding the reſt.
But yet the Work may be
ſhorten’d by the two precedent Problems, as we
ſhall ſhew in the following Examples.
ſhorten’d by the two precedent Problems, as we
ſhall ſhew in the following Examples.
Example I.
To throw a Pentagon having one Side parallel to
the Baſe Line, into Perſpective.
the Baſe Line, into Perſpective.
Let A B C D E, be the propoſed Pentagon,
11Fig. 15. wherein draw the Line B D which will be paral-
lel to A E, becauſe the Pentagon is a regular
one.
11Fig. 15. wherein draw the Line B D which will be paral-
lel to A E, becauſe the Pentagon is a regular
one.
Now find the Repreſentation of the ſaid 2242.
Lines A E and B D, and you will have the Re-
preſentation of four of the Corners of the Pen-
tagon; and to determine the Repreſentation of
the fifth Corner, find the Appearance of 3343. Line drawn from C to E, which in this Example
is parallel to A B, which is ſuppoſed parallel
to the Baſe Line.
preſentation of four of the Corners of the Pen-
tagon; and to determine the Repreſentation of
the fifth Corner, find the Appearance of 3343. Line drawn from C to E, which in this Example
is parallel to A B, which is ſuppoſed parallel
to the Baſe Line.
Example II.
To throw a Parallelogram, divided into ſeveral
other Parallelograms into Perſpective.
other Parallelograms into Perſpective.
Let A B C D be a Parallelogram, divided
44Fig. 17. into ſeveral other Parallelograms.
44Fig. 17. into ſeveral other Parallelograms.
Draw the Line O G thro’ the Eye O parallel to
the Side A D, cutting the Horizontal Line in G;
likewiſe draw O F parallel to the Side A B cutting
the Horizontal Line in F, and produce the Sides
of the Parallelogram, and the Lines dividing it,
to the Baſe Line; then from the Points wherein
A D and C B, and the Lines parallel thereto
cut the Baſe Line, draw Lines to the Point G.
Alſo from the Points wherein A B and C D and
their parallels cut the ſaid Line, draw Lines to
the Point F, whoſe Interſections with
the Side A D, cutting the Horizontal Line in G;
likewiſe draw O F parallel to the Side A B cutting
the Horizontal Line in F, and produce the Sides
of the Parallelogram, and the Lines dividing it,
to the Baſe Line; then from the Points wherein
A D and C B, and the Lines parallel thereto
cut the Baſe Line, draw Lines to the Point G.
Alſo from the Points wherein A B and C D and
their parallels cut the ſaid Line, draw Lines to
the Point F, whoſe Interſections with
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