I
n
[
]
:
=
O
u
t
[
]
=
S
i
m
s
o
n
l
i
n
e
I
n
c
e
n
t
e
r
(
X
1
)
S
t
r
a
i
g
h
t
l
i
n
e
p
e
r
p
e
n
d
i
c
u
l
a
r
t
o
t
h
e
S
i
m
s
o
n
l
i
n
e
t
h
a
t
p
a
s
s
e
s
t
h
r
o
u
g
h
t
h
e
i
n
c
e
n
t
e
r
G
e
o
m
e
t
r
i
c
l
o
c
u
s
t
h
a
t
d
e
s
c
r
i
b
e
s
t
h
e
i
n
t
e
r
s
e
c
t
i
o
n
p
o
i
n
t
o
f
t
h
e
t
w
o
s
t
r
a
i
g
h
t
l
i
n
e
s
C
i
r
c
u
m
f
e
r
e
n
c
e
o
f
t
h
e
9
p
o
i
n
t
s
O
u
t
[
]
=
θ
Deltoid (trace of Simson’s line):
I
n
[
]
:
=
O
u
t
[
]
=
θ
It is observed that both the circumference of the 9 points and the curve of the three petals are tangent to the deltoid.
