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The Orthopolar Circle
Definition: ABC is a triangle; A′B′C′ is its medial triangle; L, M, N are the feet of the perpendiculars from A, B, C respectively on a straight line, σ 1 σ 2 , σ 3 are three circles having their centres at A ′, B ′, C ′ respectively such that σ 1 passes through M and N , σ 2 through N and L , and σ...
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Published in: | Mathematical gazette 1941-12, Vol.25 (267), p.288-297 |
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Main Author: | |
Format: | Article |
Language: | English |
Subjects: | |
Online Access: | Get full text |
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Summary: | Definition: ABC
is a triangle;
A′B′C′
is its medial triangle;
L, M, N
are the feet of the perpendiculars from
A, B, C
respectively on a straight line, σ
1
σ
2
, σ
3
are three circles having their centres at
A
′,
B
′,
C
′ respectively such that σ
1
passes through
M
and
N
, σ
2
through
N
and
L
, and σ
3
through
L
and
M
Then it is readily seen that the radical axes of the three circles taken in pairs meet in a point
W
—the radical centre of the circles. Again, since
L
is a common point of σ
2
and σ
3
, their radical axis is the line through
L
at right angles to their line of centres
B
′
C
′, and hence to
BC
. Hence the lines through
L, M, N
at right angles to
BC, CA, AB
respectively meet at
W
, which is said to be the orthopole of the line
LMN
The common radical circle of σ
1
, σ
2
, σ
3
is called the
Orthopolar
circle of the line
LMN
. Let us consider a few applications of the properties of this circle and its centre. |
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ISSN: | 0025-5572 2056-6328 |
DOI: | 10.2307/3606560 |