WOLFRAM
|
DEMONSTRATIONS PROJECT
The Three-Chord Lemma
a
n
g
l
e
s
B
A
C
a
n
d
D
A
C
∠
B
A
C
≈
2
2
.
5
0
0
°
∠
D
A
C
≈
2
2
.
5
0
0
°
A
B
+
A
D
≈
3
.
6
3
7
2
A
C
c
o
s
[
∠
B
A
C
]
=
2
A
C
c
o
s
[
∠
D
A
C
]
≈
3
.
6
3
7
L
e
t
A
B
,
A
C
,
a
n
d
A
D
b
e
t
h
r
e
e
c
h
o
r
d
s
o
n
a
c
i
r
c
l
e
s
u
c
h
t
h
a
t
A
C
b
i
s
e
c
t
s
∠
B
A
D
.
T
h
e
n
A
B
+
A
D
=
2
A
C
c
o
s
(
∠
B
A
C
)
.
D
r
a
g
t
h
e
o
r
a
n
g
e
p
o
i
n
t
s
a
n
d
t
h
e
s
l
i
d
e
r
t
o
c
h
a
n
g
e
t
h
e
f
i
g
u
r
e
.