A
n
g
l
e
s
o
f
a
Q
u
a
d
r
i
l
a
t
e
r
a
l
m
∠
D
A
B
=
7
8
.
6
9
°
m
∠
A
B
C
=
8
6
.
6
3
3
°
m
∠
B
C
D
=
1
2
3
.
1
1
1
°
m
∠
C
D
A
=
7
1
.
5
6
5
°
m
∠
D
A
B
+
m
∠
A
B
C
+
m
∠
B
C
D
+
m
∠
C
D
A
=
3
6
0
.
0
0
°
●