10
Ladd, The Pascal Hexagram.
These three
lines meet in a point, namely, the Brianchom point
hence the two triangles formed by the vertical rows of
points are homologous. The sides of the first are the Pascals
and the corresponding sides of the second are
hence these three pairs of sides intersect in a line which, as it is an axis of homology corresponding to the centre of homology
we shall call the line
In the same way it may be shown that the triangle formed by any three of the four Pascals to which the triangle
belongs are homologous therewith, therefore the intersections of the four axes of homology,
with the four Pascal lines
respectively, are four points on one straight line. As this line is obtained by means of the triangle
we shall call it the line
To each triangle formed by three fundamental lines, no two of which pass through the same point on the conic, corresponds a line
of the same notation; there are
such triangles, hence there are
lines
To each
point corresponds a
line, hence there are
lines
divided into
groups of four each, which intersect corresponding
lines on the
lines.
4. The triangles
are homologous. Let us call their centre of homology
their axis
Let us say that the points
are joined by the line
and that the lines
intersect in
where the bar is drawn over the letters that are repeated. I have shown (Educational Times, Question 5698,) that
intersect in
and that
are connected by
There are
points
and
lines
Each
point is joined to
other
points by
lines, hence there are
lines
which pass by twos through the
points
and
points
which lie in twos on the
lines
The six
lines
 |
, |
 |
, |
|
 |
 |
|
intersect in pairs in three points on one straight line, viz., the
points on
hence they form the sides of a Pascal hexagon; and for a similar reason the six
points of the same notation are the vertices of a Brianchon hexagon.
5. The Brianchon hexagon formed by joining alternate vertices of
has for its sides
The conic inscribed